Diesel Trains vs Diesel Buses and Trucks (was Re: The Horror, Oh, The Horror of Car-less-ness)
James Strickland
>According to testing done (I don't remember the name of the group, but
>the data was published in one of the scholarly journals (of Gas Turbines
>etc.) the NOx g/bhp emissions of diesel electrics is around 11.0, whereas
>the current standard for new model buses and trucks is 5.0. Of course,
>the test cycles are somewhat different, so it's hard to directly compare.
The question is, though, how much power is required per unit mass of
freight/people to be moved? If trains require about half that the
equivalent buses/trucks would (and I think this is correct, mainly due
to the difference in rolling friction between steel wheel and rail and
rubber wheel and pavement), then according to your figures the amount
of NOx emissions would be roughly equal.
Did these same studies mention other pollutants?
>Remember that larger engines do not necessarily make their power with
>less pollution per unit of horsepower. It depends on a lot of factors.
Really? I am certainly no expert, but I find it hard to believe that a
diesel engine which runs at its optimum speed (as it does in a
locomotive, correct?) would produce more pullutants than an equivalent
number of truck engines operating over various speeds. I would think
that there is no physical reason why a locomotive couldn't have as good
emission equipment as that of a truck, so even if it is the case that
trains aren't less polluting now, they certainly could be made to be.
>Also remember that diesel electric trains lose energy converting the
>diesel to electricity.
Yes, but not very much.
Of course, the solution is to electrify rail lines, then the pollutants
would be decreased drastically (especially if the power didn't come
from a combustion powered plant!).
>Plus, they're carrying a lot of extra weight
>around.
Trucks carry a lot of extra weight around, too - a truck probably
weighs about 5 tons without trailer (just a guess). If you take the
weight of four locomotives (say, 800 tonnes) and divide by 200 (200
containers), you get 4 tonnes of locomotive per container. The cars
which actually hold the containers add to the train's weight as well,
but I don't know how much they weigh. Thus, I think the weight works
out to be in the same ballpark as that of a truck which could haul one
container.
>Still, I would guess that a cargo train was less polluting than a freight
>truck per pound of cargo carried, but I don't have the data to back that
>up.
Neither do I. I just assumed it was clear from all the physical advantages
trains have. Maybe someone out there can provide a more definitive answer?
>If you have more data, please post. Give us some of your knowledge of
>combustion processes, power transmission, etc., though it would be better
>if you could give some measured numbers.
I must redirect this question to others, since I am not an expert...
I can quote one potentially useful formula (which contains constants
derived from measured numbers), however. According to "The
Contemporary Diesel Spotter's Guide", the train resistance in pounds
per ton is
1.3 + 29/W + 0.045V + 0.0005AV^2/WN
where
A is the cross-sectional area of the average car in square feet
W is the weight in tons per axle
V is the speed in miles per hour
N is the number of axles per truck
This is called "The Davis Formula", and dates from 1926.
After a little more calculation, it appears that most trains require
about 1 hp/ton at 40 mph and 2 to 3 hp/ton at 60 mph, with empty trains
requiring up to 4 hp/ton at 60 mph.
--
James Strickland "No silicon heaven?!?
jstr...@cs.sfu.ca Where would all the calculators go?"
Douglas W. Jones,201H MLH,3193350740,3193382879
only on the fuel and emissions considerations, but also on the realestate
question. Most double tracked railroad mainlines in the United States are
built on rights-of-way that are 100 feet wide, and 60 foot rights-of-way
are not uncommon in some areas. A 4 lane interstate highway requires a
right-of-way that is, at minimum, around 250 feet wide, and frequently
much wider.
In addition, out of that 100 foot right-of-way, the railroad actually
disturbs about 1/3 to 1/2 of the land except in very hilly terrain. As
a result, the right-of-way frequently preserves native vegetation and
small fauna that would be destroyed by the prevailing land uses in the
area.
In contrast, interstate highway rights-of-way are frequently sized exactly
to the needs of highway construction. The entire right-of-way is typically
graded during highway development, and the majority of it is re-graded
every 10 to 20 years as repaving is undertaken. As a result, although
interstate highway rights-of-way take typically three times as much land
as is needed for a railroad right-of-way, they provide far less value for
the preservation of endangered ecosystems.
(It is worth noting that the majority of the preserved tallgrass prairie
in Illinois is on railroad rights-of-way, and it is estimated that at most
1% of the tallgrass prairie remains today, after 150 years of intensive
agricultural exploitation. Compared with this, our nation's old growth
forests are in great shape!)
Finally, if all you care about is fuel economy and pollution, the uniform
mild grades and excellent traffic control technology of railroads have a
huge effect. Railroad trains are almost always run with very slow
acceleration, slow breaking, and uniform speeds between. Trucks and busses
on the other hand, have to contend with constantly varying traffic, causing
the need for many abrupt cycles of acceleration and deceleration, and they
must routinely deal with significan hills, causing additional cycles of
heavy and light engine loading.
As a result, engine emmision figures for a railroad engine measured at
normal operating speed are likely to be close to the real average, while
the figures for a truck or bus engine are likely to differ from the average
because bench or lab measurements are unlikely to correctly take into
account the effects of the typically irregular loading faced by a road
engine.
Doug Jones
jo...@cs.uiowa.edu
Jeremy Higdon
> In article <i97...@sgi.sgi.com> jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
> >According to testing done (I don't remember the name of the group, but
> >the data was published in one of the scholarly journals (of Gas Turbines
> >etc.) the NOx g/bhp emissions of diesel electrics is around 11.0, whereas
> >the current standard for new model buses and trucks is 5.0. Of course,
> >the test cycles are somewhat different, so it's hard to directly compare.
>
>
> The question is, though, how much power is required per unit mass of
> freight/people to be moved? If trains require about half that the
> equivalent buses/trucks would (and I think this is correct, mainly due
> to the difference in rolling friction between steel wheel and rail and
> rubber wheel and pavement), then according to your figures the amount
> of NOx emissions would be roughly equal.
I think you're grossly overstating the friction of rubber/road. It
just isn't that much, especially compared to wind resistance at
typical cruise speed. Where the train should have an advantage is
in wind resistance per ton carried.
> Did these same studies mention other pollutants?
Yes, but NOx was the focus. HC and CO aren't problems for diesels.
Particulate matter was rather high, but I don't remember the number.
> >Remember that larger engines do not necessarily make their power with
> >less pollution per unit of horsepower. It depends on a lot of factors.
>
>
> Really? I am certainly no expert, but I find it hard to believe that a
> diesel engine which runs at its optimum speed (as it does in a
> locomotive, correct?) would produce more pullutants than an equivalent
> number of truck engines operating over various speeds. I would think
> that there is no physical reason why a locomotive couldn't have as good
> emission equipment as that of a truck, so even if it is the case that
> trains aren't less polluting now, they certainly could be made to be.
Trucks tend to operate at a constant speed also, but the rest of what
you say seems correct, though I'm no expert either.
> >Also remember that diesel electric trains lose energy converting the
> >diesel to electricity.
>
> Yes, but not very much.
Ok. Any idea how much "not very much" is?
> Of course, the solution is to electrify rail lines, then the pollutants
> would be decreased drastically (especially if the power didn't come
> from a combustion powered plant!).
Not really practical for freight.
> >Plus, they're carrying a lot of extra weight
> >around.
>
>
> Trucks carry a lot of extra weight around, too - a truck probably
> weighs about 5 tons without trailer (just a guess). If you take the
> weight of four locomotives (say, 800 tonnes) and divide by 200 (200
> containers), you get 4 tonnes of locomotive per container. The cars
> which actually hold the containers add to the train's weight as well,
> but I don't know how much they weigh. Thus, I think the weight works
> out to be in the same ballpark as that of a truck which could haul one
> container.
I don't think so. Rail cars empty are about the same weight of a
loaded semi, I think. About 80000 pounds. Flat cars are probably
less.
> I can quote one potentially useful formula (which contains constants
> derived from measured numbers), however. According to "The
> Contemporary Diesel Spotter's Guide", the train resistance in pounds
> per ton is
>
> 1.3 + 29/W + 0.045V + 0.0005AV^2/WN
>
> where
> A is the cross-sectional area of the average car in square feet
> W is the weight in tons per axle
> V is the speed in miles per hour
> N is the number of axles per truck
>
> This is called "The Davis Formula", and dates from 1926.
>
> After a little more calculation, it appears that most trains require
> about 1 hp/ton at 40 mph and 2 to 3 hp/ton at 60 mph, with empty trains
> requiring up to 4 hp/ton at 60 mph.
I didn't follow the calculation, but that's ok. If an 80000 pound semi
requires 200hp to maintain 60mph, it is using 5 hp/ton. But if it
only needs 100hp, that 2.5hp/ton. I wonder which number is closer.
jeremy
Jeremy Higdon
> The diesel trains versus diesel trucks and busses debate should focus not
> only on the fuel and emissions considerations, but also on the realestate
> question. Most double tracked railroad mainlines in the United States are
> built on rights-of-way that are 100 feet wide, and 60 foot rights-of-way
> are not uncommon in some areas. A 4 lane interstate highway requires a
> right-of-way that is, at minimum, around 250 feet wide, and frequently
> much wider.
Hmm. 62.5 feet per lane. I would say the minimum (remember, minimum)
would be more like 88 feet. Four 12-foot lanes and 4 10-foot shoulders.
> Finally, if all you care about is fuel economy and pollution, the uniform
> mild grades and excellent traffic control technology of railroads have a
> huge effect. Railroad trains are almost always run with very slow
> acceleration, slow breaking, and uniform speeds between. Trucks and busses
> on the other hand, have to contend with constantly varying traffic, causing
> the need for many abrupt cycles of acceleration and deceleration, and they
> must routinely deal with significan hills, causing additional cycles of
> heavy and light engine loading.
Since you mention buses, passenger trains in urban service also do
lots of starting and stopping. In intercity service, buses tend to
maintain a constant speed. Freight trucks do also. Hills are steeper
with roads, but the road is also much more direct than the typical
railroad line over mountains.
> As a result, engine emmision figures for a railroad engine measured at
> normal operating speed are likely to be close to the real average, while
> the figures for a truck or bus engine are likely to differ from the average
> because bench or lab measurements are unlikely to correctly take into
> account the effects of the typically irregular loading faced by a road
> engine.
Why? What kind of cycle does the EPA use for heavy duty emission testing?
Is this just speculation?
> Doug Jones
> jo...@cs.uiowa.edu
I really don't want to get into a truck vs. train debate (especially
in rec.railroad), since I happen to believe that trains are very useful
for freight. But trucks are too. And your post was pretty one sided.
If anyone has more information, please post.
jeremy
dave pierson
>In article <i97...@sgi.sgi.com> jer...@classic.asd.sgi.com (Jeremy Higdon)
>writes:
>>According to testing done (I don't remember the name of the group, but
>>the data was published in one of the scholarly journals (of Gas Turbines
>>etc.) the NOx g/bhp emissions of diesel electrics is around 11.0, whereas
>>the current standard for new model buses and trucks is 5.0. Of course,
>>the test cycles are somewhat different, so it's hard to directly compare.
And, more importantly(is that a word??), the regulatory requirments
are different. Highway vehicles, including turcks, have been subject
to requirments to limit emissiions that are more stringnet than those
applied to RRs. RRs (especially in California) are now faced with
requirements to limit emissions. They will bolt on the technology
from the trucks and be just as clean. (probably, on a system level,
cleaner, due to the comments in the next paras...) Also, its arguably
easier to covert (and monitor) the smaller number of d-e locos required
to move a given tonnage of freight to (say) methane, or LPG (and others)
are doing this NOW, than to equp a given number of trucks (and keep the
maintained.)
>The question is, though, how much power is required per unit mass of
>freight/people to be moved? If trains require about half that the
>equivalent buses/trucks would (and I think this is correct, mainly due
>to the difference in rolling friction between steel wheel and rail and
>rubber wheel and pavement), then according to your figures the amount
>of NOx emissions would be roughly equal.
More significantly, air resistance goes up as the cube of speed.
At (very roughly) 60mph air resistance equals other drags (I think thats
for road/rubber born traffic...) Each truck has to "punch its own hole"
in the air. A loco cuts one, and the rest of the train follows.
(This is "rough and ready analysis, but, in detail, well be found to
hold up...) Modern (freight) trains are _not_ ideally streamlined, but
"windage" loss is a design factor, and is getting consideration.
Trucks lose, here.
>>Remember that larger engines do not necessarily make their power with
>>less pollution per unit of horsepower. It depends on a lot of factors.
>Really? I am certainly no expert, but I find it hard to believe that a
>diesel engine which runs at its optimum speed (as it does in a
>locomotive, correct?)
It depends on the loco. Relatively few are actually constant speed.
Varying the speed provides better fuel efficiency.
>would produce more pullutants than an equivalent
>number of truck engines operating over various speeds. I would think
>that there is no physical reason why a locomotive couldn't have as good
>emission equipment as that of a truck, so even if it is the case that
>trains aren't less polluting now, they certainly could be made to be.
indeed.
>>Also remember that diesel electric trains lose energy converting the
>>diesel to electricity.
>Yes, but not very much.
Somewhere under 10-15%, i believe. Also, RR routing is flatter, less
hillclimbing, less over all fuel use.
>Of course, the solution is to electrify rail lines, then the pollutants
>would be decreased drastically (especially if the power didn't come
>from a combustion powered plant!).
>>Plus, they're carrying a lot of extra weight around.
huh? I/we missed the start, but i would finf this hard to believe.
>>Still, I would guess that a cargo train was less polluting than a freight
>>truck per pound of cargo carried, but I don't have the data to back that
>>up.
>Neither do I. I just assumed it was clear from all the physical advantages
>trains have. Maybe someone out there can provide a more definitive answer?
>>If you have more data, please post. Give us some of your knowledge of
>>combustion processes, power transmission, etc., though it would be better
>>if you could give some measured numbers.
>I must redirect this question to others, since I am not an expert...
What would you like top know? There are professionals, people who spend
there carreers planning and engineering transport systems. One
source of info is ASME/IEEE Joint RR Meeting transactions. Published
yearly. Professional papers on the subject show up other places, tho
I can't cite specific examples.
>I can quote one potentially useful formula (which contains constants
>derived from measured numbers), however. According to "The
>Contemporary Diesel Spotter's Guide", the train resistance in pounds
>per ton is
>1.3 + 29/W + 0.045V + 0.0005AV^2/WN
>where
>A is the cross-sectional area of the average car in square feet
>W is the weight in tons per axle
>V is the speed in miles per hour
>N is the number of axles per truck
>This is called "The Davis Formula", and dates from 1926.
>After a little more calculation, it appears that most trains require
>about 1 hp/ton at 40 mph and 2 to 3 hp/ton at 60 mph, with empty trains
>requiring up to 4 hp/ton at 60 mph.
Also doesn't include adjustments for curvature and hill climbing..
thanks
dave pierson |the facts, as accurately as i can manage,
Digital Equipment Corporation |the opinions, my own.
40 Old Bolton Rd |I am the NRA.
Stow, Mass, USA
01775 pie...@msd26.enet.dec.com
"He has read everything, and, to his credit, written nothing." A J Raffles
Wilson Heydt
>A 4 lane interstate highway requires a
>right-of-way that is, at minimum, around 250 feet wide, and frequently
>much wider.
Where does this figure come from? Eight 12-foot lanes would be 96
feet, plus shoulders and median (and, locally, many freeways don't
really *have* a median strip--and not much shoulder, either, should
come to, perhaps, 150 feet. (That is assuming that by "4 lane
interstate, you mean 4 lanes each way... If not, it would be narrower
yet.)
--Hal
--
Hal Heydt |
Analyst, Pacific*Bell | If you think the system is working,
510-823-5447 | Ask someone who's waiting for a prompt.
whh...@pbhya.PacBell.COM |
Mike Lipsie MPU
>In article <1993Jun1.2...@cs.sfu.ca>, jstr...@cs.sfu.ca (James Strickland) writes:
>> In article <i97...@sgi.sgi.com> jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
>> >According to testing done (I don't remember the name of the group, but
>> >the data was published in one of the scholarly journals (of Gas Turbines
>> >etc.) the NOx g/bhp emissions of diesel electrics is around 11.0, whereas
>> >the current standard for new model buses and trucks is 5.0. Of course,
>> >the test cycles are somewhat different, so it's hard to directly compare.
>>
>
>Yes, but NOx was the focus. HC and CO aren't problems for diesels.
>Particulate matter was rather high, but I don't remember the number.
I did not read the original article (in the journal) but I will assume that
the focus on only NOx was valid in context.
However, that focus is not valid in this newsgroup and especially not
under the current Subject: line. If it is desired to compare pollutants
from the various means of transportation, all pollutants should be considered.
Not just those that support the pro (or anti) car enthusiasts.
--
Mike Lipsie (work) mli...@ca.merl.com
Mitsubishi Electronic Research Laboratory (home) mi...@dosbears.UUCP
Michael Moroney
>In article <1993Jun1.2...@cs.sfu.ca>, jstr...@cs.sfu.ca (James Strickland) writes:
>> In article <i97...@sgi.sgi.com> jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
>> >Also remember that diesel electric trains lose energy converting the
>> >diesel to electricity.
>>
>> Yes, but not very much.
>Ok. Any idea how much "not very much" is?
"Not very much" in that they do it in the first place because it is more
efficient than using a conventional transmission/drivetrain. Part of that
efficiency is due to the narrow range of speeds the locomotive engine
has to run in.
I think another reason is that the railroads haven't found an engineer
with a clutch leg strong enough to shift gears for a 15,000 ton freight
train yet.. :-)
-Mike
Carl J Lydick
=freight/people to be moved? If trains require about half that the
=equivalent buses/trucks would (and I think this is correct, mainly due
=to the difference in rolling friction between steel wheel and rail and
=rubber wheel and pavement), then according to your figures the amount
=of NOx emissions would be roughly equal.
Actually, I'd expect the differences in aerodynamics between a train and
buses/trucks to make more of a difference than the differences in rolling
friction.
=Of course, the solution is to electrify rail lines, then the pollutants
=would be decreased drastically (especially if the power didn't come
=from a combustion powered plant!).
They've done that in the northeast corridor. But it's got its drawbacks.
About 3 years ago, somewhere between Baltimore and New York, a piece of cargo
fell off a train and took out one of the towers supporting the catenary. It
took something like 6 hours to get diesel locomotives out to all the stranded
trains and clear the tracks. During that period, there was no train service in
the northeast corridor.
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: CA...@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL
Disclaimer: Hey, I understand VAXen and VMS. That's what I get paid for. My
understanding of astronomy is purely at the amateur level (or below). So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it. If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.
Operator
BTU/Passenger Mile, in thousands:
Intercity Bus - 0.939 BTUs per mile
TGV Train - 1.147 BTUs per mile
ASEA (X2000) - 1.388 per mile
German Maglev - 1.673 BTUs per mile
Motorcycles - 2.269 "
Intercity Rail (Amtrak) - 2.637 (does not say if electric or diesel)
Commuter Rail - 3.138 "
Transit Rail (LRT?) - 3.534 "
Transit Bus - 3.761 "
Automobile - 3.841 "
Pickup truck - 4.762 "
Airliner - 4.763 "
/Mark
Judd.w...@xerox.com
Jeremy Higdon
> jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
>
> >In article <1993Jun1.2...@cs.sfu.ca>, jstr...@cs.sfu.ca (James Strickland) writes:
> >> In article <i97...@sgi.sgi.com> jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
>
> >> >Also remember that diesel electric trains lose energy converting the
> >> >diesel to electricity.
> >>
> >> Yes, but not very much.
>
> >Ok. Any idea how much "not very much" is?
>
> "Not very much" in that they do it in the first place because it is more
> efficient than using a conventional transmission/drivetrain. Part of that
> efficiency is due to the narrow range of speeds the locomotive engine
> has to run in.
I was wondering about a percentage. Someone else said 10-15%.
> I think another reason is that the railroads haven't found an engineer
> with a clutch leg strong enough to shift gears for a 15,000 ton freight
> train yet.. :-)
>
> -Mike
I thought the main reason was that transmissions just couldn't handle the
strain of a 3000hp engine. I don't think efficiency was as big a concern
as whether they could make it work.
jeremy
Jeremy Higdon
You misunderstood. HC and CO are relatively low for diesels, and are not
much of a problem any more anyway. The latest research I've heard about
suggests that NOx is the main contributor to smog and particulates are
major contributors to cancer. Gasoline powered engines used to emit more
NOx than diesels, but now they are much less. There are virtually no
particulate emissions from gasoline engines, while diesels emit quite a
lot (except for recent diesel buses, which are down to about 10% of
where they were 5 years ago (.1 g/bhp vs. 1.1) -- in 1994 the standard
drops to .05).
So when considering all pollutants, cars probably look even better
until natural gas powered trains come along. Though the discussion
really centered around trucks, or at least that was my understanding.
jeremy
christopher pontani
> In article <1993Jun1.2...@cs.sfu.ca>, jstr...@cs.sfu.ca (James Strickland) writes:
> They've done that in the northeast corridor. But it's got its drawbacks.
> About 3 years ago, somewhere between Baltimore and New York, a piece of cargo
> fell off a train and took out one of the towers supporting the catenary. It
> took something like 6 hours to get diesel locomotives out to all the stranded
> trains and clear the tracks. During that period, there was no train service in
> the northeast corridor.
But the total advantages of having electrified rails definately
outweigh the disadvantages caused by such an infrequent event such as
this one described above. Besides, for commuter operations, electric
trains accelerate quicker than diesels.
- Chris P.
Scott Lurndal
|> In article <1993Jun1.2...@news.uiowa.edu>, jones@pyrite (Douglas W. Jones,201H
|> MLH,3193350740,3193382879) writes:
|> > The diesel trains versus diesel trucks and busses debate should focus not
|> > only on the fuel and emissions considerations, but also on the realestate
|> > question. Most double tracked railroad mainlines in the United States are
|> > built on rights-of-way that are 100 feet wide, and 60 foot rights-of-way
|> > are not uncommon in some areas. A 4 lane interstate highway requires a
|> > right-of-way that is, at minimum, around 250 feet wide, and frequently
|> > much wider.
|>
|> Hmm. 62.5 feet per lane. I would say the minimum (remember, minimum)
|> would be more like 88 feet. Four 12-foot lanes and 4 10-foot shoulders.
|>
*are* on about 250 feet of right-of-way. There is a very wide median
(quite often with stands of trees between the two sets of lanes e.g. east
of IC on I-80) and wide zones on either side of the freeway. When the
freeway was built, this was the standard right-of-way for rural interstates.
I can't imagine, however, that I-80 through Iowa has had much of an effect
either positive or negative on the wildlife of iowa - or the plains grasslands
for that matter (except for the occasional heifer that breaks through a fence
and wanders onto the freeway - fresh steaks :=)
In california urban areas, where space is at more of a premium, the minimums are
more in the range specified by Jeremy.
Ranjit Bhatnagar
[re Electrification]
> They've done that in the northeast corridor. But it's
>got its drawbacks. About 3 years ago, somewhere between
>Baltimore and New York, a piece of cargo fell off a train
>and took out one of the towers supporting the catenary. It
>took something like 6 hours to get diesel locomotives out to
>all the stranded trains and clear the tracks. During that
>period, there was no train service in the northeast
>corridor.
And a couple of days ago, a guy got a haircut on a bridge
and tied up traffic for three hours. Obstructions of
various types are problems regardless of the power source...
Here in Philadelphia, in the fall, the commuter trains (all
electric) are often hung up on wet leaves. They apparently
coat the tracks and make them so slippery that the trains
have to run at reduced speed.
--
"Trespassers w" ran...@gradient.cis.upenn.edu
The surface of the water where they move swiftly about in curves.
Bob MacDowell
pie...@msd26.enet.dec.com (dave pierson) writes:
>In article <1993Jun1.2...@cs.sfu.ca>, jstr...@cs.sfu.ca
>(James Strickland) writes...
> More significantly, air resistance goes up as the cube of speed.
> At (very roughly) 60mph air resistance equals other drags (I think thats
> for road/rubber born traffic...) Each truck has to "punch its own hole"
> in the air. A loco cuts one, and the rest of the train follows.
> (This is "rough and ready analysis, but, in detail, well be found to
> hold up...) Modern (freight) trains are _not_ ideally streamlined, but
> "windage" loss is a design factor, and is getting consideration.
> Trucks lose, here.
Especially when compared to RoadRailer. One of the advantages of having
less than six inches between the trailers (besides anti-theft) is
*incredible* aerodynamic efficiency. Norfolk Southern typically assigned
one GP40 to an 80-car RoadRailer train, and it rolled right along at 70.
This was also noticeable at trackside when one went by. Not nearly the
wind blowing around etc. It just sort-of slinked by!
>>Really? I am certainly no expert, but I find it hard to believe that a
>>diesel engine which runs at its optimum speed (as it does in a
>>locomotive, correct?)
> It depends on the loco. Relatively few are actually constant speed.
> Varying the speed provides better fuel efficiency.
Freight locomotives are pretty damned efficient. They are said to spend
1/3 of their time in idle, 1/3 in Run 8 (very efficient and low-emission),
and 1/3 in intermediate throttle positions.
The F40PH, the prevalent American passenger locomotive, is somewhat
inefficient and relatively high in NOx emission, becuase it spends most
of its time with the engine spinning at top speed, but generating little
power... a very inefficient operating mode.
"He has read everything, and to his credit, quoted it all." -Bob :-)
Bob MacDowell
jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
>I thought the main reason was that transmissions just couldn't handle the
>strain of a 3000hp engine. I don't think efficiency was as big a concern
>as whether they could make it work.
They not only need to transmit 3000 horsepower, they need to do it at while
stopped. Electric transmission allows the locomotive to apply full power
for long enough to get the whole freight train moving, and to do it without
wearing components like clutches (!) or gears. The new AC traction
motor locomotives, have no wearing parts at all in the electric drive.
It's all fixed windings and semiconductors.
-Bob
dave pierson
>In article <1993Jun1.2...@cs.sfu.ca>, jstr...@cs.sfu.ca (James
Strickland) writes:
>> In article <i97...@sgi.sgi.com> jer...@classic.asd.sgi.com (Jeremy Higdon)
>> writes:
>> >Also remember that diesel electric trains lose energy converting the
>> >diesel to electricity.
>> Yes, but not very much.
>Ok. Any idea how much "not very much" is?
large size alternators run 90%+ efficient, ditto large size motors.
say 80% efficient in round numbers. Trucks lose some in the
transmission (gear box) and differential. I don't have numbers handy,
but the diff, particularly, is lossy.
>> Of course, the solution is to electrify rail lines, then the pollutants
>> would be decreased drastically (especially if the power didn't come
>> from a combustion powered plant!).
>Not really practical for freight.
hmmmmm? That would come as a heckuva shock (8)>>) to the PRR, the VGN,
the N&W and the CMStP&P, all of which moved large quantities of freight
under wires. And to essentially all the RRs in Europe who move freight
under wires. And to the Sishen-Saldena(?) of Namibia which currently
holds the world record for longest/heaviest freight train. The whole
line is electrified.... And the Australian heavy haul lines. and the
Chinese. And the Russians....
My guess is that trucks may have a mild advantage on the weight issue, since
truck/trailers aren't required to be strong enough to tow 100 odd other trucks.
OK. Let me inject some real numbers (tm).
(They are from the AAR (American Ass'n of Railroads))
307 ton-miles per gallon [of diesel]
one ton is moved 307 miles with a gallon of fuel. (that was 1987,
previous years are lower, the increase is steady.)
Surely some one can get an equivalent figure for trucks?
1,531 ton-miles per employee.
Note that employee costs (wages, etc are an order of magnitude
(roughly) more than fuel costs, for RRs. I suspect even more so for
trucks, tho differing labor agreements may affect this.
Chris Webster
>In article <1993Jun1.2...@news.uiowa.edu> jones@pyrite (Douglas W. Jones,201H MLH,3193350740,3193382879) writes:
>>A 4 lane interstate highway requires a
>>right-of-way that is, at minimum, around 250 feet wide, and frequently
>>much wider.
>
>Where does this figure come from? Eight 12-foot lanes would be 96
>feet, plus shoulders and median (and, locally, many freeways don't
>really *have* a median strip--and not much shoulder, either, should
>come to, perhaps, 150 feet. (That is assuming that by "4 lane
>interstate, you mean 4 lanes each way... If not, it would be narrower
>yet.)
>
> --Hal
>
For safety's sake, a highway should have open areas on the side of the
shoulders. Cars (very often, in fact) go off the highway and, if there
is not a grassy area (I recall it being 30'-40') the cars plow into
obstructions such as trees, severly injuring or killing the occupants.
If there is a grassy area, the driver is usually able to recover and,
unless he gets stuck in mud, is able to continue on his/her way.
So, add 3(40') = 120' (median and two outside shoulders) and you'll get
250'.
(BTW, being a recent Civil Engineering graduate, I could find references
on this, but they're most likely to be an expensive textbook.)
--Chris
Lewis E. Wolfgang, Code 541
Not to mention the difficulty in feeding torque to 4 or 6 axles, on two
different trucks. You loose quite a bit of efficiency in a gear train.
Take a look at a three-truck Shay steam locomotive to see what a drive
shaft/bevel gear system looks like. Ours only manages 12 MPH, and what a
cacophony of clattering and whurring to behold!
Steam locomotives had an advantage in that they produced the greatest torque
at zero rpm.
Good Iron
Lewie
wolf...@nosc.mil
San Diego Railroad Museum
Peter Brown
Newsgroups reduced to rec.railroad.
In article <i9g...@sgi.sgi.com> jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
[LOTS of stuff deleted]
In article <1993Jun1.2...@cs.sfu.ca>, jstr...@cs.sfu.ca (James Strickland) writes:
> Of course, the solution is to electrify rail lines, then the pollutants
> would be decreased drastically (especially if the power didn't come
> from a combustion powered plant!).
Not really practical for freight.
I'm not sure I understand this remark. Several American railroads had
large, successful electric freight operations for several decades
(PRR, NYNH&H, VGN, N&W, GN, MILW). Other, smaller lines (Black Mesa &
Lake Powell, for example) continue to use electric traction in freight
service quite successfully. For that matter, I'm sure our European
friends could give us lots of examples of freight electric operations
that are alive and well. Finally, in the late seventies when diesel
fuel was more expensive, there was serious consideration of
large-scale electrification for freight service in the U.S.
It should be noted also that Conrail dropped the ex-PRR and NYNH&H
electric freight operations, not because of any fundamental limit on
the technology, but because of the high cost imposed by Amtrak for
running freight trains over the electrified Northeast Corridor. Other
factors played a part, of course. The equipment was old, and
replacements would have had to be custom-designed; they wanted to run
freights through from electrified to non-electrified territory (all
the more so since Amtrak had just made the electrified main lines so
expensive); and advances in diesel-locomotive technology, combined
with the drop in fuel costs in the early eighties, made the advantage
of the electrics too small to justify the high first cost of extending
the electrification.
Don't get me wrong - electrification has its drawbacks (that high
first cost is probably the biggie, but there are others).
"Not really practical for freight" seems to me to overstate those,
however. If I am misunderstanding, please let me know; maybe you're
using "practical" in a different sense from the one I heard.
Peace,
--Peter
--
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
"'He is not here; for he has been raised, as he said.'" - Matt. 28:6
Lewis E. Wolfgang, Code 541
Interesting thread. I wonder if this "Maglev" report is truly unbiased.
I would think that the numbers for hauling pounds-of-passengers would
differ from those of pounds-of-freight. Passengers have to have lots
of volume around them and I would think you would have to include
a comfort factor somewhere to give an accurate relative efficiency
ranking.
I am surprised by the intercity bus numbers being so much better than
intercity rail, is that a herring I smell?
Lewis E. Wolfgang, Code 541
Interesting thread. One wonders at the impartiality of a study funded by a
MagLev project though.....
I would think that passengers are rather expensive to haul compared to freight.
The packing density is not as great (except in Japan :>) and I would think
that a fair comparison would have to include a comfort factor.
I recall hearing that rail was second only to ship for hauling freight
efficiently.
In the case of the Maglev number, would 1.673 BTU/mile include the cost
of cryogenically cooling the support/propulsion coils? To get a fair
comparison one has to consider ALL the costs, overt and covert, of the
entire transportation system.
I believe that the only way long-distance trucks can compete with rail
is because of the hidden subsidy of not paying their full share of the
interstate highway costs. This may be true for intercity buses too.
Good Iron,
Lewie
wolf...@nosc.mil
Albert H. Titus
I have often wondered how trucks carrying freight could compete with trains in
efficiently transporting large amounts of whatever, but I think there is another
aspect involved: quantity.
Obviously a single train with two or three engines is capable of transporting much more
than two or three tractor-trailers, but industry these days do not operate as they
did quite a few years ago. The practice of just-in-time (JIT) shipping calls for
parts to be brought in as needed, rather than brought in every so often in huge
quantities such as rail provides. Supposedly this reduces the need for keeping track
of large inventories and storing of the materials for long periods of time. Also
this is supposed to make the industry able to react more quickly when they have to
retool or make a product change. Clearly this can't apply to all industries, but each
that uses it means slightly less rail freight handled :(
I'm not saying the method of JIT shipping is good or bad overall, just that trains
excel in transporting large amounts of "stuff" to particular areas and this doesn't
seem to fit in with how industries are running these days.
Of course this doesn't apply to passengers. That requires a Trains vs Planes debate.
-------------------------------------------------------------------------------------
Opinions are mine alone. No they're not, they're mine! Now hold on you two they're
mine. Oh yeah? Ok the three of me better step outside and settle this!
Albert Titus
E. Michael Smith
I don't follow this ... Diesels have some very low numbers for CO and HC,
so it really isn't of much interest to report them when comparing two
different diesel engines (and not of much interest for comparison
with car gasoline engines either...). The problem with Diesels is
the NOX and particulates, so you would rationally expect to look at
where the problems were rather than where they did well naturally ...
You have to fix NOX and particulates to have acceptable Diesels. Only
after you get past that point is a discussion of HC and CO really of
interest...
--
E. Michael Smith e...@apple.COM
'Whatever you can do, or dream you can, begin it. Boldness has
genius, power and magic in it.' - Goethe
I am not responsible nor is anyone else. Everything is disclaimed.
E. Michael Smith
The capital costs of catenary or third rail and all the power transmission
gear are 'non-trivial' especially on long hauls cross country... The
reason much of Europe is electric and much of the USA is diesel is that
we had low population density and stringing all that electric line cost
more and wasted more energy in transmission losses than it was worth.
As we, USA, get more high population density corridors, such as the
northeast, with high track usage rates and high local electric power
availability, we will electrify more corridors. Till then, it still
makes much more sense to put the generator on the train and fuel up
enroute when crossing Kansas ...
The use of the electric motor makes providing TRACTION at low speed
much easier and more efficient. Direct drive could be done with
a torque converter, but you would lose more than you do in the
electric conversion... Just think of it as an electric clutch and
transmission that is more efficient that the hydraulic alternatives...
Jeremy Higdon
> In article <i9g...@sgi.sgi.com>, jer...@classic.asd.sgi.com (Jeremy Higdon)
> writes...
>
> hmmmmm? That would come as a heckuva shock (8)>>) to the PRR, the VGN,
> the N&W and the CMStP&P, all of which moved large quantities of freight
> under wires. And to essentially all the RRs in Europe who move freight
> under wires. And to the Sishen-Saldena(?) of Namibia which currently
> holds the world record for longest/heaviest freight train. The whole
> line is electrified.... And the Australian heavy haul lines. and the
> Chinese. And the Russians....
Let me clarify. I didn't see wires being very practical for long distance,
say from SF to Chicago, freight. If the wires are already there, that's
another thing entirely. But your Namibia example would be a counter-example
to what I expected, though I don't have a good feeling for how long
Sishen-Saldena would be. Is it more or less than 1000 miles? So, do you
think the SP or AT&SF would find it practical to convert to electric catenary?
If so, do you know why they haven't?
> My guess is that trucks may have a mild advantage on the weight issue, since
> truck/trailers aren't required to be strong enough to tow 100 odd other trucks.
>
> OK. Let me inject some real numbers (tm).
> (They are from the AAR (American Ass'n of Railroads))
>
> 307 ton-miles per gallon [of diesel]
> one ton is moved 307 miles with a gallon of fuel. (that was 1987,
> previous years are lower, the increase is steady.)
>
> Surely some one can get an equivalent figure for trucks?
Thank you for the numbers. I wish I knew more certain what diesel
mileage for trucks was, but I believe an 80000 lb. truck can get
around 7 or 8 mpg. The payload is probably somewhere around 60000
pounds. 60000 lbs at 8 mpg is 240 ton-miles per gallon. This may
be a high estimate.
> 1,531 ton-miles per employee.
> Note that employee costs (wages, etc are an order of magnitude
> (roughly) more than fuel costs, for RRs. I suspect even more so for
> trucks, tho differing labor agreements may affect this.
Is there a rec.trucking? One could get info there. I suspect that
trucking companies tend to have better (for the company) labor
agreements (and, of course, many have none at all, since the company
is the trucker).
jeremy
Jeremy Higdon
>
> As we, USA, get more high population density corridors, such as the
> northeast, with high track usage rates and high local electric power
> availability, we will electrify more corridors. Till then, it still
> makes much more sense to put the generator on the train and fuel up
> enroute when crossing Kansas ...
>
> The use of the electric motor makes providing TRACTION at low speed
> much easier and more efficient. Direct drive could be done with
> a torque converter, but you would lose more than you do in the
> electric conversion... Just think of it as an electric clutch and
> transmission that is more efficient that the hydraulic alternatives...
Something that may be of interest is that a Canadian bus manufacturer
(Orion) is developing a diesel-electric transit bus. I don't know
many details, but it has something to do with the requirement for a
low floor, where there isn't room for a traditional drive train.
It also makes dual-power buses more practical, since there isn't as
much duplicated drivetrain.
jeremy
Bob MacDowell
> Note that employee costs (wages, etc are an order of magnitude
> (roughly) more than fuel costs, for RRs. I suspect even more so for
> trucks, tho differing labor agreements may affect this.
The #1 cost of a truck owner-operator, is fuel. As you said, fuel is a
far less significant issue for railroads.
Remember this. At some point in the future, fuel *will* start getting
expensive. Watch what happens to the economics of truck vs. rail...
will be interesting.
-Bob
Bob MacDowell
>did quite a few years ago. The practice of just-in-time (JIT) shipping calls for
>parts to be brought in as needed, rather than brought in every so often in huge
>quantities such as rail provides. Supposedly this reduces the need for keeping track
>of large inventories and storing of the materials for long periods of time. Also
<wow, a bit dizzy from the word-wrap... must be nice having an X-terminal :-)>
Anyway, the railroads can operate 'just in time' as well as the trucks can.
They just have to want to. A GM plant in St. Louis was the Raison D'Etre
of the original Norfolk Southern RoadRailer. They captured a hell of a lot
of business that way, that would've been truck. Many railroads run special
trains or consists in "hot" trains specifically for JIT plants.
A recent quote by the president of Wisconsin Central was that the railroads
haven't taken advantage of the smaller crews to run shorter, faster trains
that go different places to improve service.
In essence, 'Where's our big savings?'
-Bob
M00...@mbvm.mitre.org
jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
>
>Something that may be of interest is that a Canadian bus manufacturer
>(Orion) is developing a diesel-electric transit bus. I don't know
>many details, but it has something to do with the requirement for a
>low floor, where there isn't room for a traditional drive train.
>It also makes dual-power buses more practical, since there isn't as
>much duplicated drivetrain.
>
>
Students of the transit industry will remember gasoline-electric busses
(and a few Diesel electrics) made by a bunch of manufacturers, even including
Yellow Coach and GM, in the 1920s and 30s. And also, the "all-service coaches"
operated by Public Service in New Joisy that operated as trolley coaches
where there was wire and gas-electrics where there wasn't. Do you suppose
the Seattle folks think they invented that idea?
Len Bachelder Archives Committee, Boston and Maine RR Historical Society
MITRE Corp. Secretary, Massachusetts Bay Railroad Enthusiasts
Bedford MA 01730 Member, 470 Railroad Club
<M00...@mitre.org> <- NOTE Address change!
"Amazing love, how can it be that Thou, my God, should'st die for me!"
- Charles Wesley
John B Coxey
Been reading the posts about trucks etc. Figure I could throw in
my two cents worth.
> Weight:
An empty COE (Cab Over Engine - Ie. Flat faced tractor) weighs
18,000# (#=Pounds USA), without any fuel or driver posessions or
driver. This is for the industry standard 250HP, 9 or 10 speed, 3axle
tractor used for hauling general commodity freight in the USA. (Ie.
Schneider, NAVL, Mayflower, JBHunt, etc.).
In fact, one must carry a manufacturer's weight certification
for both the tractor and trailer unit. The trailer weight certificate
will be located in a metal box at the nose of the trailer. Sometimes,
the trailer registration will be located there as well.
> Payload:
A normal 5 axle semi, can legally have a total vehicle weight
of 80,000#, which must be spread over the axles, with the following
limitations.
12,000# -- steering axle.
34,000# -- drive avles.
34,000# -- trailer axles.
--------
80,000# -- total weight of payload and vehicle.
The maximum I usually hauled was around 52,000#, and was in the
form of powdered limestone (Northern Mass area - Pfitzer chemical).
Anything above that weight is pratically impossible to scale out, axle
wise.
Most paper loads (newsprint rolls, or kraft paper for
cardboard) weigh around 47,000 - 49,000#. You can slide the 5th
wheel on the tractor as well as the trailer tandems to get the
axle weights correct.
> Horsepower:
Most commercial company owned tractors are 250hp. However,
the industry range is from 200hp to 450hp. I have driven a 350hp
for NAVL (North American Van Lines), when I was a driver-trainer. Nice
to cruise at 75mph across Texas and Utah.
Fuel consumption is around 5.5 - 6.5 mpg for the average
driver. Of course, some promotional advertisements claim better
results. The KW Anteater claims to get 7.9 - 9.1 mpg, but neither
NAVL nor I believe it.
My fuel costs for 1985 (I was an owner operator for Mayflower
Transit) were around $30,000 for 125,000 miles. So when we talk a 10
or 15% increase in mpg, it means alot dollar wise.
-------
Hope this helps.
Latre,
John P. Coxey
(jb...@unix.cis.pitt.edu)
John B Coxey
About JIT (Just In Time shipping).
I think (my own personal reasons / experience) the reason alot of
companies today ship via truck is due to a combination of things.
#1. One phone call can have a semi at your door, and your product
delivered tomorrow.
#2. Trucks can go from point A to point B. With a train you still
need to transfer the freight from the train to a truck then
deliver it to the customer's door.
#3. Look how many small companies there are today. Do realize how
much finished product it takes to fill just one 48' semi. Plus
alot of the loads have 3-4 stops on them. I think it would be
rather difficult for a r.r to deliver one or two trailer loads
of freight to 4 or 5 different locations.
#4. Freight (general commodity) is random. One company may ship
30 loads out one week and then only 4 or 5 for the next 3
weeks.
#5. Pay scale. Tractor-trailer drivers (JBHunt/Schneider/etc) are
non-union, and are paid by the mile. So what if it takes the
guy 4 or 5 hours to get the stuff of the trailer (alot of times
you gotta do it yourself), you don;t get paid. If you don;t
like it then we (the customer) will find someone else. There
is a thing called "detention time", just try collecting it.
(hah!).
If you ship via rail. You gotta pay the guy to deliver the
frieght from the train to truck transfer point, then drive
to the delivery point. Don;t forget, this guy will want to
be paid for an 8 hour day, at union scale. Also gotta figure
in the idle time for equipment.
John Coxey
(jb...@unix.cis.pitt.edu)
Stephen M. Webb
>In article <1993Jun3.0...@lynx.dac.northeastern.edu> cpon...@lynx.dac.northeastern.edu (christopher pontani) writes:
>>In article <1uj69e...@gap.caltech.edu>, ca...@SOL1.GPS.CALTECH.EDU (Carl J Lydick) writes:
>>
>> But the total advantages of having electrified rails definately
>>outweigh the disadvantages caused by such an infrequent event such as
>>this one described above. Besides, for commuter operations, electric
>>trains accelerate quicker than diesels.
>
>The capital costs of catenary or third rail and all the power transmission
>gear are 'non-trivial' especially on long hauls cross country... The
>reason much of Europe is electric and much of the USA is diesel is that
>we had low population density and stringing all that electric line cost
>more and wasted more energy in transmission losses than it was worth.
>
>As we, USA, get more high population density corridors, such as the
>northeast, with high track usage rates and high local electric power
>availability, we will electrify more corridors. Till then, it still
>makes much more sense to put the generator on the train and fuel up
>enroute when crossing Kansas ...
Compound those facts with the fact that AC motor technology has been slow to
develop. Traction (electric trains) have traditionally used DC motors for
a number of reasons (better control, cheaper manufacture and maintenance),
but the distribution of 25000 VDC is difficult, requiring frequent substations
(which require land purchase), frequent feeders, large-diameter cabling
(using lots of expensive copper), and so forth. AC power comes straight off
the grid, travels well in smaller diameter wires, and requires fewer and
smaller substations. In fact, with AC power, the catenary can actually be
the power distribution system (with DC, there's a fat copper wire running
parallel to the track carrying the current, with very frequent feed wires to
the catenary).
Now that improved AC traction technology and advanced AC chopper controls
are on the market, watch for icreased use of electric traction technology.
--
Stephen M. Webb ---- Doubleplus bellyfeel unfrink ----- ste...@teleride.on.ca
We're sorry, you call cannot be completed as dialled. Please hang up and try
your call again. This is a recording. We're sorry, your call cannot be comp
dave pierson
>In article H...@netcom.com, bob...@netcom.com (Bob MacDowell) writes:
>>Followups set to rec.railroad.
>>
>>jer...@classic.asd.sgi.com (Jeremy Higdon) writes:
>>>I thought the main reason was that transmissions just couldn't handle the
>>>strain of a 3000hp engine. I don't think efficiency was as big a concern
>>>as whether they could make it work.
>>
>>They not only need to transmit 3000 horsepower, they need to do it at while
>>stopped. Electric transmission allows the locomotive to apply full power
>>for long enough to get the whole freight train moving, and to do it without
>>wearing components like clutches (!) or gears. The new AC traction
>>motor locomotives, have no wearing parts at all in the electric drive.
>>It's all fixed windings and semiconductors.
Some nits:
The diesel electric does not deliver full HP at stand still.
That _would_ require infinite torque. The HP at .00001 MpH is
limited by the weight available for traction, (short term) and the
thermal limits on the motors.
Another major advantage of electric drive is the smoothness, and
continuity of application of the forces. This is important for two
reasons:
Whacking gear teeth with 3000HP (or equivalent torque)
as when changing gears WILL break the teeth.
Transients due to shifting physical gears generate transients
in TE that break draw bars and damage freight.
>Not to mention the difficulty in feeding torque to 4 or 6 axles, on two
>different trucks. You loose quite a bit of efficiency in a gear train.
>Take a look at a three-truck Shay steam locomotive to see what a drive
>shaft/bevel gear system looks like. Ours only manages 12 MPH, and what a
>cacophony of clattering and whurring to behold!
12 MPH is a desing limit. Shays are geared that way because thats
whats needed, not due to losses in the gear train. (tho losses in
any right angle drive are high, and to do the same thing at speed
usually one goes to a Beyer-Garrat or other articulation scheme.
>Steam locomotives had an advantage in that they produced the greatest torque
>at zero rpm.
Still not as good as electric (diesel or straight) since the torque
is a function of the crank angle. Quatered cranks help, but it
still pulses. The electric _also_ produces its greatest torque at
standstill, and the torque is dead smooth.
christopher pontani
> (Orion) is developing a diesel-electric transit bus. I don't know
> many details, but it has something to do with the requirement for a
> low floor, where there isn't room for a traditional drive train.
> It also makes dual-power buses more practical, since there isn't as
> much duplicated drivetrain.
>
> jeremy
>
manufactured CNG buses. They look very similar to their diesel
counterparts, but there is a dome on the top that holds the fuel
and other components. This enables the floor to be lower. These buses
are already in service in several cities (of which I can't remember, but
I saw them in an issue of Passenger Transport) including Nassau County,
on Long Island. When I first saw it, I had to do a triple take.
- Chris P.
dave pierson
Trans-Siberian in Russia is electrified. Single track. Doing nicely, thanks.
The reasons the US has not got more electrification are complex. The energy
efficiency difference between diesel electric and straight electric is real
thin. A couple of things (imo) have tipped the US away from more
electrification:
Relatively high crew costs lead to longer trains leads to poor load
factors leads to expensive electrification.
Almost unique in the world, the US RR system was, at the time in private
hands. Its a LOT cheaper, paying market interest rates, to
diesel-electrify than it is to straight-electrify. It can be done
one loco at a time, paid for out of savings from displacing the
steamers. For a government owned RR's interest rates (to pay for large,
lump, capital expenditures have a tendency to (look) lower.
(one can debate endlessly "real" costs, a swamp i decline to start into,
tho the results can be intriguing...)
Douglas W. Jones,201H MLH,3193350740,3193382879
by pie...@msd26.enet.dec.com (dave pierson):
> Still not as good as electric (diesel or straight) since the torque
> is a function of the crank angle. Quatered cranks help, but it
> still pulses. The electric _also_ produces its greatest torque at
> standstill, and the torque is dead smooth.
Torque on an electric motor is only smooth if you have enough armature
poles. A 2 pole armature has the same dead-center problems as a single
double acting steam cylinder. A 4 pole armature (rarely used) has the
same degree of uniformity of torque as a pair of double-acting cylinders
quartered. Three pole armatures are used, and they provide pretty jerky
torque (nonetheless, some model builders, notably Fleischman, have made
excellent use of such motors.
Most DC traction motors have very large numbers of poles, I admit, so
they have smoothness equivalent to an engine with equally many cylinders.
Three cylinder engines such as the larger shays and a few mainline engines
provided smoother torque than the usual two cylinders.
DC motors with carefully skewed armatures can offer even more uniform
torque -- nothing equivalent can be done with pistons, but skewing is
only used (to my knowledge) on small motors with small numbers of armature
poles.
Doug Jones
jo...@cs.uiowa.edu
Harris Minter
>Here in Philadelphia, in the fall, the commuter trains (all
>electric) are often hung up on wet leaves. They apparently
>coat the tracks and make them so slippery that the trains
>have to run at reduced speed.
At the Six Flags Over Georgia amusement park, it was a common practical
joke to cover the tracks with STP oil additive. Nobody went
nowhere.....
dave pierson
Jones,201H MLH,3193350740,3193382879) writes, in part:
>From article <1993Jun4.2...@ryn.mro4.dec.com>,
>by pie...@msd26.enet.dec.com (dave pierson):
>
>> Still not as good as electric (diesel or straight) since the torque
>> is a function of the crank angle. Quatered cranks help, but it
>> still pulses. The electric _also_ produces its greatest torque at
>> standstill, and the torque is dead smooth.
>
>Torque on an electric motor is only smooth if you have enough armature
>poles. A 2 pole armature has the same dead-center problems as a single
>double acting steam cylinder. A 4 pole armature (rarely used) has the
>same degree of uniformity of torque as a pair of double-acting cylinders
>quartered. Three pole armatures are used, and they provide pretty jerky
>torque (nonetheless, some model builders, notably Fleischman, have made
>excellent use of such motors.
and most applications of traction motors have at least four, further
smoothing things. (tho the axles are not coupled, so if any ONE
exceeds slip point, it may well spin out....)
Mark Wilson
|manufactured CNG buses. They look very similar to their diesel
|counterparts, but there is a dome on the top that holds the fuel
|and other components. This enables the floor to be lower. These buses
Just be very careful around low slung bridges. ;*)
--
Mob rule isn't any prettier merely because the mob calls itself a government
It ain't charity if you are using someone else's money.
Wilson's theory of relativity: If you go back far enough, we're all related.
Mark....@AtlantaGA.NCR.com
William J. Earl
> In article 7...@spectrum.xerox.com, ro...@ocp.mc.xerox.com (Operator) writes:
> >Just for your information, from page 5-9 of the New York State Technical & Economic Maglev Evaluation report dated June 1991, produced by the New York State Energy Research and Develeopment Authority:
> >
> >BTU/Passenger Mile, in thousands:
> >Intercity Bus - 0.939 BTUs per mile
> >TGV Train - 1.147 BTUs per mile
> >ASEA (X2000) - 1.388 per mile
> >German Maglev - 1.673 BTUs per mile
> >Motorcycles - 2.269 "
> >Intercity Rail (Amtrak) - 2.637 (does not say if electric or diesel)
> >Commuter Rail - 3.138 "
> >Transit Rail (LRT?) - 3.534 "
> >Transit Bus - 3.761 "
> >Automobile - 3.841 "
> >Pickup truck - 4.762 "
> >Airliner - 4.763 "
> I am surprised by the intercity bus numbers being so much better than
> intercity rail, is that a herring I smell?
I imagine that all of the above are based on the vehicle being
loaded to capacity, as opposed to being loaded to usual occupancy.
Buses often run with low load factors. If the load factor is only
0.3, the bus is up to 3.13 BTUs per passenger mile.
--
William J. Earl w...@esd.sgi.com
Digital Sight and Sound Division 415-390-2128
Mail Stop 1L-945 FAX 415-390-6159
Silicon Graphics, Inc.
Bob MacDowell
>Torque on an electric motor is only smooth if you have enough armature
>poles. A 2 pole armature has the same dead-center problems as a single
>double acting steam cylinder. A 4 pole armature (rarely used) has the
>same degree of uniformity of torque as a pair of double-acting cylinders
>quartered. Three pole armatures are used, and they provide pretty jerky
>torque (nonetheless, some model builders, notably Fleischman, have made
>excellent use of such motors.
>Most DC traction motors have very large numbers of poles, I admit, so
>they have smoothness equivalent to an engine with equally many cylinders.
The traction generators on early alcos had 305 (!) poles on the armature.
The traction motors had a bunch to, in the general neighborhood of 100.
The brushes actually sat on several at once. So yes, power was *real*
smooth.
Wonder how they'll do it with AC traction motors?
Douglas W. Jones
by bob...@netcom.com (Bob MacDowell):
> The traction generators on early alcos had 305 (!) poles on the armature.
> The traction motors had a bunch to, in the general neighborhood of 100.
> The brushes actually sat on several at once. So yes, power was *real*
> smooth.
>
> Wonder how they'll do it with AC traction motors?
The big advantage of 3-phase AC is that, in theory, it can be used in
an induction motor to generate perfectly smooth torque. Shaded pole
induction motors come close with conventional single-phase AC. You can
come even closer with single phase AC if you convert to 3-phase using
appropriate phase shifting networks (capacitors and inductors) outside
the motor.
Doug Jones
jo...@cs.uiowa.edu
dave pierson
(Douglas W. Jones) writes...
The modern applications use multiple inverters to make 3 phase,
variable frequency AC from a dc link. The "smoothness" depends on the
stator windingd and the number of "bars" in the rotor.
Douglas W. Jones,201H MLH,3193350740,3193382879
by pie...@msd26.enet.dec.com (dave pierson):
>>The big advantage of 3-phase AC is that, in theory, it can be used in
>>an induction motor to generate perfectly smooth torque. ...
>
> The modern applications use multiple inverters to make 3 phase,
> variable frequency AC from a dc link. The "smoothness" depends on the
> stator windingd and the number of "bars" in the rotor.
Yes, you need lots of bars in the motor rotor of an induction motor to get
near ideal behavior, but even tiny inexpensive induction motors typically
have over 20 bars, so that's not much of a problem. Making 3-phase power
with choppers is a bit more difficult, though, because the ideal behavior
of 3-phase motors only occurs when the power is sinusoidal. The simple
square-wave chopper generates a lousy approximation of a sine wave, and this
will lead to irregular torque on any induction motor driven by it.
High frequency choppers that generate low frequency approximations of sine
waves will smooth out the torque quite nicely. These use technology similar
to that in switching DC power supplies, but they produce a sinusoidal output
instead of a fixed DC output.
Doug Jones
jo...@cs.uiowa.edu
Robert Coe
> poles. A 2 pole armature has the same dead-center problems as a single
> double acting steam cylinder. A 4 pole armature (rarely used) has the
> same degree of uniformity of torque as a pair of double-acting cylinders
> quartered. Three pole armatures are used, and they provide pretty jerky
> torque (nonetheless, some model builders, notably Fleischman, have made
> excellent use of such motors.
>
> Most DC traction motors have very large numbers of poles, I admit, so
> ders. Three cylinder engines such as the larger shays and a few main-
> line engines provided smoother torque than the usual two cylinders.
Articulated locos had four cylinders, didn't they? Were they set up so
that the rear two cylinders were out of phase with the front two?
___ _ - Bob
/__) _ / / ) _ _
(_/__) (_)_(_) (___(_)_(/_______________________________________ b...@1776.COM
Robert K. Coe ** 14 Churchill St, Sudbury, Massachusetts 01776 ** 508-443-3265
dave pierson
>jones@pyrite (Douglas W. Jones,201H MLH,3193350740,3193382879) writes:
>> Torque on an electric motor is only smooth if you have enough armature
>> poles. A 2 pole armature has the same dead-center problems as a single
>> double acting steam cylinder. A 4 pole armature (rarely used) has the
>> same degree of uniformity of torque as a pair of double-acting cylinders
>> quartered. Three pole armatures are used, and they provide pretty jerky
>> torque (nonetheless, some model builders, notably Fleischman, have made
>> excellent use of such motors.
>>
>> Most DC traction motors have very large numbers of poles, I admit, so
>> they have smoothness equivalent to an engine with equally many cylin-
>> ders. Three cylinder engines such as the larger shays and a few main-
>> line engines provided smoother torque than the usual two cylinders.
>Articulated locos had four cylinders, didn't they? Were they set up so
>that the rear two cylinders were out of phase with the front two?
It was _undefined_. The only coupling between the wheelsets was the
steam piping. I vaguely recall reading that there was a "problem"
which lead to the wheelsets becoming synchronized, so that vibration
_increased_. Something about the interaction of the back pressures.
I may be _wrong_ on that, but indpendent wheelsets were independent.
No specific control of the phase existed.
Shays, etc, are an exception. The drive shaft maintains phasing.
They, too, are articulated... Geared locos were also smoother in that
they were "geared down", with multiple power pulses per driver
revolution.
Daniel Burstein
Newsgroups: alt.planning.urban,ba.transportation,sci.energy,rec.railroad
Subject: Dieasl-electric SHIPS, was: Re: Diesel Trains vs Diesel Buses and
Trucks (was Re: The Horror, Oh, The Horror of Car-less-ness)
References: <1993May30.0...@pbhya.PacBell.COM> <1uj69e...@gap.caltech.edu> <1993Jun3.0...@lynx.dac.northeastern.edu> <1993Jun3.1...@michael.apple.com>
In the thread of diesal-electric locomotives, I'd just like to point out
that an issue of New Scientist about two months ago reported that there
had been an increase in orders for diesal-electric oil freighters.
Most ships are direct drive, where the enginese more or less are connected
to the propellor shaft. In a ship you're talking about -huge- amounts of
horsepower....
The article didn't say much about the control advantages, but explained
that this was being doen for safety. seems a major cause of ship engine
breakdown is water leaks in which salt water from the ocean contaminates
the pressure loops (I don't quite understand, but it kind of seems logical)
the d-e ships, on the other hand, will have two or more generators, each
indenpendant, so if one gets knocked out of service, there will still be
enough electicity to power the engines (or rather, motors). Perhaps a bit
more slowly, but at least enough to keep the ship away from hull eating rocks.
han...@physc1.byu.edu
> Articulated locos had four cylinders, didn't they? Were they set up so
> that the rear two cylinders were out of phase with the front two?
>
> ___ _ - Bob
> /__) _ / / ) _ _
> (_/__) (_)_(_) (___(_)_(/_______________________________________ b...@1776.COM
> Robert K. Coe ** 14 Churchill St, Sudbury, Massachusetts 01776 ** 508-443-3265
Nope. Each engine in an articulated is independent. After all, how
would you maintain any kind of synchronization when one of the engines
slipped while starting and the other didn't? This was not all that
uncommon, because very few if any articulated engines had exactly the
same weight on the drivers of both engines, let alone differences in
other details like track.
Doug Hansen Han...@physc1.byu.edu
Charley Wingate
>Articulated locos had four cylinders, didn't they? Were they set up so
>that the rear two cylinders were out of phase with the front two?
Given the articulation there really was no way to control this. A little
slipping in the front or back and you could have any combination.
The _George Emerson_, B&O's only duplex (4-4-4-4, non-articulated) had one
set of drivers turned down to help keep the two sets of machinery out of
step. Duplexes were prone to slipping, though, so I don't know whether,
say, N&W would have bothered with this on a Y6b.
--
C. Wingate + "The peace of God, it is no peace,
+ but strife closed in the sod.
man...@cs.umd.edu + Yet, brothers, pray for but one thing:
tove!mangoe + the marv'lous peace of God."
J.R. Stoner
;In article <TgsR5B...@1776.COM>, b...@1776.COM (Robert Coe) writes:
;> Articulated locos had four cylinders, didn't they? Were they set up so
;> that the rear two cylinders were out of phase with the front two?
;Nope. Each engine in an articulated is independent. After all, how
;would you maintain any kind of synchronization when one of the engines
;slipped while starting and the other didn't? This was not all that
;uncommon, because very few if any articulated engines had exactly the
;same weight on the drivers of both engines, let alone differences in
;other details like track.
That sounds right. As far as I know the only connection between any of the
cylinders is merely the exhaust delivery from the high-pressure (smaller)
cylinder into the valve chest of the low-pressure (larger) cylinder.
An interesting aside, I recently saw a picture of Baldwin's 50,000th loco
being erected. It was an experimental articulated unit that had the
primary (high-pressure) valve gear mounted where you would expect it, but
there was a single third (low-pressure) cylinder mounted ventrally and
crosswise to the waist of the boiler. What was the ostensible purpose of this
design? Was there some kind of mechanical through-fitting to both sides
of the cylinder and steam chest that did work on the rear engines? It still
makes my brain hurt to attempt to understand any running gear (not present in
the picture) for this beast.
--
In 1911/and strident voices raised high/Votes! Votes for women, was the cry.
Titanic was sinking/and death was nigh/Boats! Boats for women, was the cry.
J.R. Stoner, MWA - asg...@plx.com - sun.com!plx!plxsun!asgard
Andrew Waugh
>Articulated locos had four cylinders, didn't they? Were they set up so
>that the rear two cylinders were out of phase with the front two?
No. There was no linkages between the front and rear cylinders of
articulated locomotives. Depending on slightly differing wheel
diameters and slippages the two engine units would vary in phase.
andrew waugh
Wes Barris
|>
|> An interesting aside, I recently saw a picture of Baldwin's 50,000th loco
|> being erected. It was an experimental articulated unit that had the
|> primary (high-pressure) valve gear mounted where you would expect it, but
|> there was a single third (low-pressure) cylinder mounted ventrally and
|> crosswise to the waist of the boiler. What was the ostensible purpose of this
|> design? Was there some kind of mechanical through-fitting to both sides
|> of the cylinder and steam chest that did work on the rear engines? It still
|> makes my brain hurt to attempt to understand any running gear (not present in
|> the picture) for this beast.
There are probably a number of steam engines that were designed this way.
Off hand I can think of three in existence today:
- #60000, a Baldwin 4-10-2 displayed at the Franklin Inst., Philadelphia
- #5021, an SP ALCO 4-10-2 displayed at the LA Co. Fairplex, Pomona, CA
- #9000, a UP ALCO 4-12-2 displayed at the LA Co. Fairplex, Pomona, CA
They each had a third cylinder located between and above the other (normal)
two cylinders. There was some kind of gear/linkage system to transfer the
motion from this central piston to one of the axles.
From what I can remember reading, this design was unsuccessful mainly
because of maintenance problems with the third cylinder/linkage assembly.
Can anyone shed some more light on this subject?
--
o O O O O o o o o o o o o . . . . . . .
__________ ___ ___ __ _
/_______|--`--|_ _|--=-==---|_ _|--,_|__|_ |-+-------`____________,
| ||_| / - | / - \ | || ________ | |
|_|___/------------|----__---------|------|||__|__|__| |Southern Pacific Lines|
|_|____________/-------{__}---------------{__}_______|=|_________ ________|
/_(o)=(o) ( )( )( )( ) [__] ( )( )( )( ) [__]--(o) (o)(o)(o)-----(o)(o)(o)
===============================================================================
Wes Barris PH: (612) 626-8090
Minnesota Supercomputer Center, Inc. Email: w...@msc.edu
;;;;RA01
>> 307 ton-miles per gallon [of diesel] TRAINS
>Thank you for the numbers. I wish I knew more certain what diesel
>mileage for trucks was, but I believe an 80000 lb. truck can get
>around 7 or 8 mpg. The payload is probably somewhere around 60000
>pounds. 60000 lbs at 8 mpg is 240 ton-miles per gallon. This may
>be a high estimate.
>
to throw in my two bits, I was told by a trucker a couple years ago that
a full rig will get 3-4 mpg. This would suggest that jeremy's estimate
should be halved to 120 ton-miles per gallon, which would suggest that
trains are much more efficient than trucks.
(of course, this trucker was driving the Rockies on steep, high altitude
roads, so his mileage may be below average...)
will the real numbers please stand up?
brian
Peter Brown
In article <1993Jun9.2...@plx.com>, asg...@plx.com (J.R. Stoner) writes:
|>
|> An interesting aside, I recently saw a picture of Baldwin's 50,000th loco
|> being erected. It was an experimental articulated unit that had the
|> primary (high-pressure) valve gear mounted where you would expect it, but
|> there was a single third (low-pressure) cylinder mounted ventrally and
|> crosswise to the waist of the boiler. What was the ostensible purpose of this
|> design? Was there some kind of mechanical through-fitting to both sides
|> of the cylinder and steam chest that did work on the rear engines? It still
|> makes my brain hurt to attempt to understand any running gear (not present in
|> the picture) for this beast.
Wes> There are probably a number of steam engines that were
Wes> designed this way. Off hand I can think of three in
Wes> existence today:
Wes> - #60000, a Baldwin 4-10-2 displayed at the Franklin
Wes> Inst., Philadelphia
Wes> - #5021, an SP ALCO 4-10-2 displayed at the LA Co.
Wes> Fairplex, Pomona, CA
Wes> - #9000, a UP ALCO 4-12-2 displayed at the LA Co.
Wes> Fairplex, Pomona, CA
Wes> They each had a third cylinder located between and above
Wes> the other (normal) two cylinders. There was some kind of
Wes> gear/linkage system to transfer the motion from this
Wes> central piston to one of the axles.
Wes> From what I can remember reading, this design was
Wes> unsuccessful mainly because of maintenance problems with
Wes> the third cylinder/linkage assembly.
Wes> Can anyone shed some more light on this subject?
Three-cylinder locomotives were built both as compounds, like #60000,
and as simple locomotives (all three cylinders get steam straight from
the boiler), like #5021 and #9000. The linkage assembly was the same
for both: the main rod of the middle cylinder drove a crank axle on
one set of driving wheels. The side rods took care of transmitting
that power to the other driving axles. The three cylinders were set
120 degrees out of phase, to give the smoothest possible torque. This
torque curve was the major reason for using three cylinders, being
smoother than you could get from a two-cylinder engine.
The valve on the middle cylinder could be driven by its own valve gear
(this was done on the #60000), or by a set of combining levers from
the outer two cylinders (effectively taking a linear combination of
their motion - this was used on the #5021 and #9000).
Wes is basically right about the problems with these engines; almost
everything connected with that middle cylinder was inaccessible and
thus hard to maintain. (J. R.'s hurting brain had the right idea
:-).) The problem was worse with compounds (#9000, for example, ran
for nearly thirty years on the U.P.; no railroad would even buy
#60000), but it was significant even with the simple engines, and the
three-cylinder fad died after about half-a-dozen years. The crank
axle was particularly troublesome, being prone to break under the
stresses of American service. Three-cylinder had a bit more success
abroad, however; Sir Nigel Gresley, who invented the combining-lever
arrangement used on #5021 and #9000, used the same system in a long
series of hugely successful locomotives for Britain's London and North
Eastern Railway.
Hope this helps,
--Peter
--
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
"I will pour out my spirit on all flesh; your sons and your daughters
shall prophesy, your old men shall dream dreams, and your young men
shall see visions." - Joel 2:28
Dave Nelson
|> - #5021, an SP ALCO 4-10-2 displayed at the LA Co. Fairplex, Pomona, CA
|>
|> From what I can remember reading, this design was unsuccessful mainly
|> because of maintenance problems with the third cylinder/linkage assembly.
|>
|> Can anyone shed some more light on this subject?
I refer you to 'Three Barrels of Steam', by Jim Boyonton, who wrote
about the SP engines of this type. Jim worked the Western Pacific
for about 40 years, firing steam and later as an engineer. He was
a photographer too. I understand he passed away about a year ago. I
don't have his book but I'll wager he knew what he was writing about.
Dave
dave pierson
>In article <1993Jun8....@physc1.byu.edu> han...@physc1.byu.edu writes:
>;In article <TgsR5B...@1776.COM>, b...@1776.COM (Robert Coe) writes:
>;> Articulated locos had four cylinders, didn't they? Were they set up so
>;> that the rear two cylinders were out of phase with the front two?
>
>;Nope. Each engine in an articulated is independent. After all, how
>;would you maintain any kind of synchronization when one of the engines
>;slipped while starting and the other didn't? This was not all that
>;uncommon, because very few if any articulated engines had exactly the
>;same weight on the drivers of both engines, let alone differences in
>;other details like track.
>
>That sounds right. As far as I know the only connection between any of the
>cylinders is merely the exhaust delivery from the high-pressure (smaller)
>cylinder into the valve chest of the low-pressure (larger) cylinder.
True enough. In the case of a COMPOUND, ARTICULATED engine. It was
quite possible to have a non articulated, compund engine (more common
internatioanlly than in the US) OR an articulated, noncompound engine.
(I am not enough of a stenie to reel off examples of each... In any
case, most _compund_ engines could be "simpled" for starting, providing
torque at the expense of efficiency. Suitable valving was provided.)
Tim Kirby
: >>>>> On Thu, 10 Jun 1993 15:04:37 GMT, w...@uf.msc.edu (Wes Barris) said:
: In article <1993Jun9.2...@plx.com>, asg...@plx.com (J.R. Stoner) writes:
:
: Wes> There are probably a number of steam engines that were
: Wes> designed this way. Off hand I can think of three in
: Wes> existence today:
:
: everything connected with that middle cylinder was inaccessible and
: thus hard to maintain.
Of course, if you want to get really complicated look to the GWR (UK Great
Western Railway) Castles and Kings - Four cylinders (two inside, two outside)
with Walschaerts valve gear between the frames on the same front axle as the
crank for the two inner cylinders... the valve motion for the outer cylinders
was passed through the frames in the front of the locomotive through a
rocker linkage. You want maintenance problems ?...
Tim
--
Tim Kirby --------- Cray Research Inc., Eagan, MN, USA ----------- t...@cray.com
Disclaimer: I disclaim, therefore I am. Be warned ...
-------------------------------------------------------------------------------
When all else fails, Immortality may always be assured by spectacular error(JKG)
Chris Bell
believe that it is the steam pressure that causes the otherwise
independent units to synchronise.
In New South Wales (just south of Newcastle), as recently as the seventies
there was a regular run from a colliery (Fassifern) hauled by two
Garratts. The train backed out from the colliery branch, then headed
straight into a 1:40 bank from a standing start. It was a very spectacular
operation! Anyway, not only would the front and back drivers synchronise
on the locos, but both locos would be synchronous before they were halfway
up the bank. This would change if a unit slipped, but they would soon
synchronise again. Whatever the reason for synchronism, it must depend
on the forces on the drivers.
There are many recordings of this operation, and the synchronism is quite
obvious.
Chris Bell
(ex New South Welshmen)
Iain Campbell
|>
|> Of course, if you want to get really complicated look to the GWR (UK Great
|> Western Railway) Castles and Kings - Four cylinders (two inside, two outside)
|> with Walschaerts valve gear between the frames on the same front axle as the
|> crank for the two inner cylinders... the valve motion for the outer cylinders
|> was passed through the frames in the front of the locomotive through a
|> rocker linkage. You want maintenance problems ?...
|>
locos were built and operated for years by European roads, but these designs
were always discarded in North America as being either too difficult to maintain or
prone to breakage. What was it that the Europeans got right that we couldn't??
iain
dotesseyegeedotesseyegeedotesseyegeedotesseyegeedotesseyegeedotesseyegee
dotesseyegee dotesseyegee
dotesseyegee ia...@acsserv1.ryerson.ca dotesseyegee
dotesseyegee dotesseyegee
dotesseyegeedotesseyegeedotesseyegeedotesseyegeedotesseyegeedotesseyegee
cho...@vms.ocom.okstate.edu
> In article <1993Jun10.2...@hemlock.cray.com>, t...@palm34.cray.com (Tim Kirby) writes:
> |>
> |> Of course, if you want to get really complicated look to the GWR (UK Great
> |> Western Railway) Castles and Kings - Four cylinders (two inside, two outside)
> |> with Walschaerts valve gear between the frames on the same front axle as the
> |> crank for the two inner cylinders... the valve motion for the outer cylinders
> |> was passed through the frames in the front of the locomotive through a
> |> rocker linkage. You want maintenance problems ?...
> |>
> But did they have maintenance problems ??? - I know hundreds of 3 and 4 cylinder
> locos were built and operated for years by European roads, but these designs
> were always discarded in North America as being either too difficult to maintain or
> prone to breakage. What was it that the Europeans got right that we couldn't??
>
> iain
of 2-8+8-2 (USA-dwellers who have never seen a Garratt should find a book
and learn to appreciate them, they are fine locomotives). Gresley had his
conjugated three cylinder valve gear at each end, and the thing worked fine
mostly.
The New Zealand railways were sold on the idea for a really
powerful loco on 3 ft 6 in gauge (one might say a really _useful_ engine
for Thomas afficionados), but the design was a disaster. Sadly so, because
the S.African, Rhodesian and E.A.R. Garratts with four cylinders (two at
each end were (and still are, some of them) conspicuously successful.
I think that the crux of the matter lies in the fact that British
and some European railways were built at a time when the limitations to
rail travel were unknown quantities: consequently the permanent way was
overbuilt (with the first Tay Bridge being a notable exception). In doing
so, certain railways were blessed with the ability to construct locomotives
which had extremely rigid frames. The rigidity of the frame kept inside and
outside cylinders in alignment for greater periods of time, hence less down
time in the shed for servicing.
Baldwins had a unique frame which was designed to flex somewhat,
because of the less uniform construction of the U.S. permanent way. This
precluded more than two cylinders, unless you mounted them on the same
crosshead, as did Sam Vauclain, with his compound system: high and low
pressure cylinders on the same crosshead (Fascinating!) (someone is going
to comment about Heislers and Shays ...I know). The consequence of the
difference in style was to aid U.S. export of locomotives to underdeveloped
countries, in spite of favourable trading status for Britain.
In the Boer war, Winston Churchill remarked that American
locomotives were more reliable than British ones in S.Africa... The reason
he did not know, but you do now!
As to the GWR Stars, Castles and Kings (all time favourite locos,
though A3s, A4s and P2s are not far behind), G.J. Churchward was asked once
(by the G.W.R. board of directors) why his engines were more expensive than
Webb's (of the LNWR, a competitor and designer of remarkably awful engines)
" Because one of mine could pull two of his bloody things backwards!" was
the reply.
Under the right conditions and with the right coal, the Castle
class was extremely powerful (for its size) fast, reliable and fuel
efficient. Who could ask for more? Unfortunately the U.S. couldn't provide
the right conditions.
Regards, David.
******Disclaimer!, Datclaimer.*******************************************
Peter Brown
In article <1993Jun10.2...@hemlock.cray.com>, t...@palm34.cray.com (Tim Kirby) writes:
|>
|> Of course, if you want to get really complicated look to the GWR (UK Great
|> Western Railway) Castles and Kings - Four cylinders (two inside, two outside)
|> with Walschaerts valve gear between the frames on the same front axle as the
|> crank for the two inner cylinders... the valve motion for the outer cylinders
|> was passed through the frames in the front of the locomotive through a
|> rocker linkage. You want maintenance problems ?...
Iain> But did they have maintenance problems ??? - I know
Iain> hundreds of 3 and 4 cylinder locos were built and
Iain> operated for years by European roads, but these designs
Iain> were always discarded in North America as being either
Iain> too difficult to maintain or prone to breakage. What
Iain> was it that the Europeans got right that we couldn't??
The conditions were just different. (1) European trains, especially
freight trains, never approached the weights of ours. That led to
smaller locomotives, with less weight per axle and less thrust per
cylinder; those lower forces, in turn, led to less trouble from crank
axles and inside cylinders. (2) Maintenance wasn't as big a part of
the budgetary picture for European railroads as for American ones,
particularly because of the high cost of labor (and the low cost of
fuel) here. So our railroads never had the incentive to *make* such
things work that the European roads had.
Tim Kirby
: In article <1993Jun10.2...@hemlock.cray.com>, t...@palm34.cray.com (Tim Kirby) writes:
: |> Of course, if you want to get really complicated look to the GWR (UK Great
: |> You want maintenance problems ?...
: But did they have maintenance problems ??? ......
: What was it that the Europeans got right that we couldn't??
Good question. In the later years of steam in England, British Railways designed
and built their so-called Standard Class locomotives which were notable for
such features as all-outside motion - built for easy maintenance. There can be
no question that working on a King between the frames is.. if not "difficult"..
certainly not "easy". I suspect one of the issues has to be the actual amount
of work the locomotives did; this is not to say the European locomotives did
not work hard, but very few - if any - got to do continuous runs hauling the
kind of loads comonly found in the USA. The non-stop track mileage just wasn't
there in a lot of cases. It might be interesting to look at some of the
continental european locomotives that did the long haul runs (the Orient
Express sort of thing) for comparison. What sort of motive power did they use ?
(I have no idea offhand ... that's a question, folks !)
Dave Hodge
>
> The three cylinders were set
> 120 degrees out of phase, to give the smoothest possible torque.
>
This makes sense, but raises another question: were the drivers of three-
cylinder locomotives 'thirded' rather than quartered?
Another poster asks about linkage between the two engines of articulated
locomotives. The two engines were independent, and when there was wheel
slip, it was usually only the front engine which slipped. In the UP's film
about the Big Boys, 'Last of the Giants', there is a shot of a Big Boy
starting where the REAR engine slips. Quite spectacular. The rest of the
film is great, too, even the cartoons of Anatole Mallet and his hand
cranked winch. It's recently become available on video tape. Tom Madden
may recall when I was program chairman of our club and borrow a copy of
the 16mm film from the UP. We nearly wore the thing out.
Dave Hodge KF0XD Hewlett Packard
da...@hpfcdjh.fc.hp.com User-Interface Hardware Lab
(303) 229-2141 (voice) Systems Technology Division
(303) 229-4515 (FAX) Ft. Collins, CO
Michael Stimac
>Articulated locos had four cylinders, didn't they? Were they set up so
>that the rear two cylinders were out of phase with the front two?
Assuming you're talking about rod locomotives, the answer is they
were not "set up" to be out-of-phase. However they would sometimes
be out-of-phase due to the fact that they ran at independent speeds.
It didn't matter how you set them up, each engine was free to run
at its own pace. Very often, the front engine would slip while
accelerating; typically the phase varied at random. In another
posting Dave points out that some steam pressure effects could
tend to get the engines into an ongoing phase.
Non-articulated Duplex locomotives experienced similar slipping
difficulties. A few steam duplexii actually were fitted with
anti-slip devices on the forward engine!
Dave has already covered geared articulateds which are necessarily
in phase. I doubt that any particular phase angle was specified
or maintained.
Michael Stimac
--
Michael Stimac
(415) 355-8889
ro...@tymnet.com
These opinions are not necessarily anyone's but my own.
Harris Minter
>Another poster asks about linkage between the two engines of articulated
>locomotives. The two engines were independent, and when there was wheel
>slip, it was usually only the front engine which slipped. In the UP's film
>about the Big Boys, 'Last of the Giants', there is a shot of a Big Boy
>starting where the REAR engine slips. Quite spectacular. The rest of the
I've seen Bobby Saxton slip the rear engine on N&W 1218.......
AJ Stradling
: Of course, if you want to get really complicated look to the GWR (UK Great
: Western Railway) Castles and Kings - Four cylinders ... etc.
: You want maintenance problems ?...
:
equiped sheds, and built sheds to match. Pits were standard for use
in locomotive preparation.
Stars, Castles and Kings were difficult to prepare and clean
between the frames due to the motion getting in the way, but the motion
gets in the way on all GW two cylinder locomotives as well, these all
have inside valve gear systems (usually Churchward setting Stephenson
link gear). The outside cylinders of all GWR four-cylinder machines
were worked by rocker arms, only two sets of Walcheart gear was fitted,
each set driving the two cylinders on the same side of the locomotive.
It isn't really very complicated at all.
On the subject of maintenance and multiple cylinders, all
Swindon-built (GWR) locomotives had their frames set up accuratly,
using Karl Zeiss Optical Equipment (german opticics manufacturer).
This meant the frames were set EXACTLY where the drawing said they
were supposed to be, and ensured that a standard part WOULD fit any
locomotive using that part in a matter of minutes. Stories abound
of new connecting rods being fitted to locomotives IN STATIONS while
the locomotive is being coupled to its train. How truthful this is
I'm not sure, but it is possible.
Ian J. Stradling EAMIL aj_s...@pat.uwe.ac.uk
Roger Mitchell
locomotives and had the enviable record of hauling more ton miles of freight
per pound of coal consumed than any other type of locomotive on that road.
When worked to their maximum capacity their fuel consumption was a modest
3 tons per hour. The D&RGW also had some highly successful 3 cylinder
locomotives that lasted until the end of steam.
Roger Mitchell
Master Mechanic and President
Fort Collins Municipal Railway
MichaelisPR
In the old, traditional Mallet locomotives, the exhaust steam from
the high-pressure cylinders on the rear set of drivers was re-used
by the low-pressure cylinders on the front set of drivers. Prior
to the installation of bypass valves, engineers, when starting a
train, often found it necessary to slip the rear drivers deliberately,
as this was the only way to get sufficient quantities of steam up to
the front drivers. (Note that these comments apply only to locos
that have separate high- and low-pressure cylinders, which, by the
way, is not the case with a "Big Boy.")
-- Paul Michaelis
Martin Beer
> : In article <1993Jun10.2...@hemlock.cray.com>, t...@palm34.cray.com (Tim Kirby) writes:
> : Of course, if you want to get really complicated look to the GWR (UK Great
> : Western Railway) Castles and Kings - Four cylinders ... etc.
> : You want maintenance problems ?...
> :
> The GWR designed locomotives to be maintained in properly
> equiped sheds, and built sheds to match. Pits were standard for use
> in locomotive preparation.
> Stars, Castles and Kings were difficult to prepare and clean
> between the frames due to the motion getting in the way, but the motion
> gets in the way on all GW two cylinder locomotives as well, these all
> have inside valve gear systems (usually Churchward setting Stephenson
> link gear). The outside cylinders of all GWR four-cylinder machines
> were worked by rocker arms, only two sets of Walcheart gear was fitted,
> each set driving the two cylinders on the same side of the locomotive.
> It isn't really very complicated at all.
Even over a pit things are a bit tight. The saving of valve gear components
by only having two sets was quite considerable though.
Stanier did not take this arrangement with him to the LMS in 1933,
probably because it was already fealt too difficult for the northern company
to maintain. Hence why the Princesses and Coronations had the valve gear
on the outside, even though the boilers were very much in the Swindon
tradition. In Edwardian times, when Churchwood laid down the ground
rules for the classic Twentieth Century Swindon product, showing the
workings of a locomotive was considered quite rude, rather like
a lady showing her ankles.
> On the subject of maintenance and multiple cylinders, all
> Swindon-built (GWR) locomotives had their frames set up accuratly,
> using Karl Zeiss Optical Equipment (german opticics manufacturer).
> This meant the frames were set EXACTLY where the drawing said they
> were supposed to be, and ensured that a standard part WOULD fit any
> locomotive using that part in a matter of minutes. Stories abound
> of new connecting rods being fitted to locomotives IN STATIONS while
> the locomotive is being coupled to its train. How truthful this is
> I'm not sure, but it is possible.
I don't know about this story, but the accuracy of erection was such
that Swindon's tolerences were very much less than any other Railway
Workshop in the UK. Rumour has it that when Swindon Officers were
posted to other Regions after Nationalisation they were horrified
that other workshops fitted at tolerences at which Swindon scrapped
components - hence problems in many areas. Was it Cox who was sent as CME to
Doncaster and eventually sorted out the big end problems on Gresley
Pacifics by improving setting out and fitting stronger components?
Even things like valve settings were standardised, and valves
were sent back to Swindon to be reset.
By the way, the first King, King George V, was sent to the Baltimore and Ohio
Centenary celebrations in the USA almost as soon as it was built. It made
such an impression being extremely powerful for its size (it is a 4-6-0,
and can be seen today in Swindon Railway Museum in place of Lode Star)
that a number of American steam locos had their outsides tidied up, and
one or two sported copper capped chimneys (a Swindon tradition to the
end of steam).
--
Dr. Martin Beer,
Department of Computer Science, Telephone 051-794-3672
University of Liverpool, Fax: 051-794-3715
Chadwick Tower, P.O. Box 147, EMail m...@uk.ac.liverpool.compsci
LIVERPOOL. L69 3BX. United Kingdom.
Chris Lee
>AJ Stradling (aj_s...@uwe.ac.uk) wrote:
>
>> On the subject of maintenance and multiple cylinders, all
>> Swindon-built (GWR) locomotives had their frames set up accuratly,
>> using Karl Zeiss Optical Equipment (german opticics manufacturer).
Actually it was Collett who introduced this (1923?). The first engines
built using this optical alignment equipment were (I think) the 5040
series of Castles. Even before this, Swindon was building engines more
accurately than most of the other lines.
>> This meant the frames were set EXACTLY where the drawing said they
>> were supposed to be, and ensured that a standard part WOULD fit any
>> locomotive using that part in a matter of minutes. Stories abound
>> of new connecting rods being fitted to locomotives IN STATIONS while
>> the locomotive is being coupled to its train. How truthful this is
>> I'm not sure, but it is possible.
>
>I don't know about this story, but the accuracy of erection was such
>that Swindon's tolerences were very much less than any other Railway
>Workshop in the UK. Rumour has it that when Swindon Officers were
>posted to other Regions after Nationalisation they were horrified
>that other workshops fitted at tolerences at which Swindon scrapped
>components - hence problems in many areas. Was it Cox who was sent as CME to
>Doncaster and eventually sorted out the big end problems on Gresley
>Pacifics by improving setting out and fitting stronger components?
Yes. E S Cox. He introduced the GWR inside big end at Doncaster. But there
had been earlier GWR influence: in (1923?) there had been an exchange when
the LNER tried out a Castle, and the GWR tried out an A1. The GWR had been
the first to use long-travel valves with a decent steam volume (Churchward
from his earliest designs). They also used higher pressured boilers and
superheating earlier than most. The Castle had (230?) lbs boiler pressure
vs the A1's 180lbs, and the A1 also had very poor valve design. The exchange
led to the A3s, with decent valves and high pressure boilers, and we all
know what great engines they were!
Also, the Gresley conjugated valve motion originated with Harry Holcroft,
who was ex-Swindon, although at the time he was working for Maunsell with
the SE&CR, and later the SR. Holcroft's implementation on the 3-cylinder
Southern engines was better than Gresley's as it used rods from the rear
of the cylinders, passing outside them to drive the conjugating levers,
while Gresley extended the valve rods through the front which meant that
the heat of the steam in the outside valves caused them to extend.
Gresley wanted to recruit Holcroft but Maunsell vetoed it. Incidentally
according to the book on the Union Pacific type (forget the author), the
UP designers visited Gresley and then took time to meet Maunsell (mis-spelt
as Mavsell in the book!). I can't imagine that they weren't introduced to
Holcroft ,even though I don't remember seeing it in HH's memoires.
These memoires make fascinating reading (Locomotive Adventure, published
by the Locomotive Publishing Co sometime in the 1950s, and in paperback
by David & Charles more recently). He started off as an apprentice at
Wolverhampton under Armstrong and lived into his 90s. Armstrong told him
that as a small boy he had run alongside the opening train on the Stockton
and Darlington in 1825.
Holcroft was the Swindon draughtsman who designed the GWR moguls, and was
also responsible for the footplate curves on the later Churchward engines
after influential folk had complained about the start, angular look of the
earlier engines.
Collett was a brilliant workshop man, hence the improvements like the
optical alignment stuff, but he was not a good locomotive designer,
in spite of the Castles, Kings, Halls and Granges which were basically
modified Churchward designs. Stanier was a better locomotive designer.
Unfortunately Collett got promoted because of his seniority and Stanier
left to take Swindon boilers, bearings etc to the LMS where he used
better frames and bogies with Swindon type boilers on the Black 5s,
Jubilees, Scots etc.
>
>Even things like valve settings were standardised, and valves
>were sent back to Swindon to be reset.
>
>By the way, the first King, King George V, was sent to the Baltimore and Ohio
>Centenary celebrations in the USA almost as soon as it was built. It made
>such an impression being extremely powerful for its size (it is a 4-6-0,
>and can be seen today in Swindon Railway Museum in place of Lode Star)
>that a number of American steam locos had their outsides tidied up, and
>one or two sported copper capped chimneys (a Swindon tradition to the
>end of steam).
A beautiful engine, built like a Rolls-Royce, fast, powerful and extremely
smooth running. Unfortunately I don't remember any doing the ton.
>--
>Dr. Martin Beer,
>Department of Computer Science, Telephone 051-794-3672
>University of Liverpool, Fax: 051-794-3715
>Chadwick Tower, P.O. Box 147, EMail m...@uk.ac.liverpool.compsci
>LIVERPOOL. L69 3BX. United Kingdom.
Chris Lee
Ian King
I never understood *why* the Churchward put the valve gear *inside*
rather than on the outside. To me it seems logical to put the
valve gear on the outside & work any inside cylinders from the
rocker arms. I have found no reference by O.S.Nock etc as to why.
Stanier, upon moving to the LMS, had seperate sets of valve gear
for his Princess Royal & Princess Coronation 4-cyl engines. It is
fairly well documented that Churchward gave advice to Stanier during
the design phase of the Princess Royals. You would have expected
the latter to have had a similar arrangement to the Kings except
the inside cyls would be worked from the outside ones. However
they didnt so maybe the rocker arm principle wasnt such a good
idea.
Regards...
.........Ian
--
ADVANCE MICRO COMPUTERS LTD & Wolverton Rail | EMAIL: ian...@amicro.demon.co.uk
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Martin Beer
> >By the way, the first King, King George V, was sent to the Baltimore and Ohio
> >Centenary celebrations in the USA almost as soon as it was built. It made
> >such an impression being extremely powerful for its size (it is a 4-6-0,
> >and can be seen today in Swindon Railway Museum in place of Lode Star)
> >that a number of American steam locos had their outsides tidied up, and
> >one or two sported copper capped chimneys (a Swindon tradition to the
> >end of steam).
> A beautiful engine, built like a Rolls-Royce, fast, powerful and extremely
> smooth running. Unfortunately I don't remember any doing the ton.
Orders were issued that GWR engines were not to attempt excessive speeds
after a Saint or a Star (I cann't remember which - but the story is
recorded I think in Taplin's extremely readable book) went somewhat
over the top on the old GWR main line and apparently started jumping off the
rails with the hammer blow. There were no speedometers fitted,
so no accurate idea of the real speed, but I was told when I was at school
it was very high (it was another Swiddon beat Doncaster by several decades
story - but was too scared to tell anyone - believe that of the GWR if you
like!).
In the Fifties Kings and Castles certainly regularly broke the ton
on service trains, and I think there are plenty of logs,
particularly on the Bristol road to prove it.
Martin