[proto] Big Boys and articulated steamers--question
John Cooley
I was sitting and looking at my plastic Big Boy model this weekend, and I came
up with a question that applies to all similar articulated steamers:
1. The Big Boy is, in a simplistic sense, two independent steam locomotives
with a common boiler.
2. The action of these engines involves all kinds of lateral and rotating
forces.
3. Nothing keeps the two individual engines "synchronized"-- that is, nothing
acts to keep both engines in the exact same phase of their cyles at the same
time.
4. Because the two engines can slip independently, the phase relationships can
therefore vary.
So here's the question:
Is there a phase relationship between the two engines that leads to the
greatest power output and the smoothest running, or does it just not matter?
Another, specific Big Boy question:
The Henry Ford Museum has a C&O Allegheny that they tout as the "largest and
most powerful steam locomotive ever built."
If my figures are correct, the Allegheny is heavier and has a larger firebox,
while the Big Boy is longer, and has larger cylinders. Not sure about peak
horsepower, but it's probably possible to carefully pick a speed where one or
the other might have the higher horsepower.
So, to make a simple comparison, which one could start a longer train on
straight, dry, level track?
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Joel Stensberg
John,
As for your first question, there never seemed to be any need to keep
the two engines in 'sync' that I have ever heard. There are even tapes
around when one of the 'engines' slipped, but the other did not.
In regard to your second question, you have not idea, none, as to what a
can of worms you have just reopened. We will how have every pundit from
here to the ends of the earth put in their two cents worth as to the
most powerful locomotive of the two. The UP locomotive is known as the
world's largest, not the most powerful, so those who wish to debate the
outcome, the line forms at the left.....
Joel
Relishing the return of the Lombardi trophy to the frozen north of Green
Bay, WI.
Daniel A. Mickey
I think that Big Boy was not a compound, but two "Simple" engines. The stack
had two sets of passages in it to take the exhaust from the two separate
engines (perhaps your model reflects this).
The original Mallet idea was to have two sets of engines in a compound
arrangement to make more economical use of steam, with the rear set being a
high-pressure set which exhausted into the front low-pressure set, and the
front set exhausted into the stack. The front set of cylinders were often
quite huge.
A lot of Mallet compound engines were converted into the two simple engine
configuration to avoid the problem of trying to keep one stalled engine from
stopping steam flow through both sets of engines. This was a major
shortcoming of the Mallet type.
Dan Mickey
ernf...@primenet.com
In <5cin1i$g...@lastactionhero.rs.itd.umich.edu>, John Cooley <bro...@umich.edu> writes:
>So, to make a simple comparison, which one could start a longer train on
>straight, dry, level track?
>
Horsepower on a steamer was very hard to measure however starting a train is a
matter of tractive force, and that number is usually available in the books. If you
can't find a number you can use 1/4 the weight on the drivers as an ESTIMATE of
tractive force (usually optimistic). Articulateds usually did not have boosters (note
disclaimer) but for other engines boosters would add to tractive force.
Horsepower dictated how fast you could move all those cars you started.
ernie fisch
Gary M. Collins
John Cooley wrote:
>
> I was sitting and looking at my plastic Big Boy model this weekend, and I came
> up with a question that applies to all similar articulated steamers:
>
> 1. The Big Boy is, in a simplistic sense, two independent steam locomotives
> with a common boiler.
> 4. Because the two engines can slip independently, the phase relationships can
> therefore vary.
>
> So here's the question:
>
> Is there a phase relationship between the two engines that leads to the
> greatest power output and the smoothest running, or does it just not matter?
>
No such relationship that I ever heard of - both engines (and unlike
your plastic Big Boy, only the *front* one swivels) are balanced
independently, so it shouldn't matter. Only problem was, as you noted,
one of weight distribution, so that the front drivers carried an equal
load. This was pretty well taken care of, but never completely solved.
> Another, specific Big Boy question:
>
> The Henry Ford Museum has a C&O Allegheny that they tout as the "largest and
> most powerful steam locomotive ever built."
> ----{snip}----
> So, to make a simple comparison, which one could start a longer train on
> straight, dry, level track?
Not sure, but probably the Allegheny. Much controversey surrounds the
claims of "most powerful", "largest", etc. This has been debated on the
net and elsewhere for years, with no definitive answer agreed upon, that
I know of. The terms are too vague, and the more precisely defined ones
are pretty evenly distributed among the various claimants (the DM&IR
"Yellowstone" is another one..). I won't get into that one. <G>
--
Gary M. Collins
gcol...@sound.net
"Common sense, ain't!" - G. Collins
MEAT7
Here are some numbers:
Big Boy (UP 4-8-8-4, 1941).
Total weight: 1,189,500 lbs
Tractive effort: 135,375 lbs
Overall length: 132ft, 10in
Allegheny (C&O 2-6-6-6, 1941).
Total weight: 1,076,000 lbs
Tractive effort: 110,200 lbs
Overall length: 130ft, 1in
Triplex (Erie 2-8-8-8-2, 1915). As mentioned in another post.
Total weight: 853,050 lbs
Tractive effort: 160,000 lbs
Overall length: 105ft 1in
The Big Boy wins in the weight and length catagories. The Triplex wins
the tractive effort catagory. The problem with the triplex was that is
wasn't able to supply enought steam for all the cylendars. All three Erie
triplexes (Virginia Railroad had one) were with drawn from service by
1925. If memory serves me, I think they were split into a 2-8-8-0, and a
0-8-2.
-Scott-
john cooley
Ah-- but I *do* have an idea of what a can of worms I opened-- I just
want to see what the pundits have to say!
I'm also (almost but could be wrong) 100% sure that the Big Boys were not
mallets, so any problems with "phase" relationships between the separate
engines would, I think have to do with any rotating or lateral forces
exerted by one engine on the other or on the entire locomotive. I suppose
those *should* all be balanced out, but then again. . . .
Janos ERO
> John Cooley wrote:
> >
> > I was sitting and looking at my plastic Big Boy model this weekend, and I came
> > up with a question that applies to all similar articulated steamers:
> >
> > 1. The Big Boy is, in a simplistic sense, two independent steam locomotives
> > with a common boiler.
Yes, this is true. But their predecessor, the Compound-Mallet ("True-Mallet") had
the high pressure engines on the rear, the low pressure engines on the front. Thus
they weren't "independent".
> > 2. The action of these engines involves all kinds of lateral and rotating
> > forces.
Yes, this was a real problem with them. I think the first versions of the
Challenger had simple connection between the front and rear engine, where the
front engine was only loaded by the boiler front through slipper plates. The later
versions had a more rigid connection, which allowed forwarding vertical forces
from the rear engine to the front one.
> > 3. Nothing keeps the two individual engines "synchronized"-- that is, nothing
> > acts to keep both engines in the exact same phase of their cyles at the same
> > time.
Yes, this was also a problem. When dragging the rear engine had more weight, thus
the front engine easier slipped. The engineer should keep care of this and
separately reduce the front engine pressure. With the "true-Mallets" this was a
smaller problem: when the front engine slipped, it consumed too much steam from
the rear engine, thus its pressure automatically dropped. On the other hand at
those engines the engineer had less control on the separate engines.
> > Is there a phase relationship between the two engines that leads to the
> > greatest power output and the smoothest running, or does it just not matter?
Probably yes, when the engines are in 45 degree it should be the smoothest. But
nobody can influence this.
> > If my figures are correct, the Allegheny is heavier and has a larger firebox,
> > while the Big Boy is longer, and has larger cylinders. Not sure about peak
> > horsepower, but it's probably possible to carefully pick a speed where one or
> > the other might have the higher horsepower.
The (horse)power is a product of the speed and the traction force. In the strict
metric system if you have the speed in m/s (meter per seconds), the traction force
in kN (kiloNewton), when multiplying them you get the power in kilowatts.
At the steam engines the limiting factor is the boiler's steam production
capacity. This means when increasing the speed the traction force will drop.
Janos Ero
Daniel A. Mickey
Rick Vera-Burgos wrote:
>
> john cooley wrote:
> >
> > Ah-- but I *do* have an idea of what a can of worms I opened-- I just
> > want to see what the pundits have to say!
> >
>
> seem to recall that this subject was hashed (and rehashed, and re-rehashed)
> out here just a few months ago.
>
> > I'm also (almost but could be wrong) 100% sure that the Big Boys were not
> > mallets, so any problems with "phase" relationships between the separate
> > engines would, I think have to do with any rotating or lateral forces
> > exerted by one engine on the other or on the entire locomotive. I suppose
> > those *should* all be balanced out, but then again. . . .
>
> compound steam engine built for use in this country since 1920. The only
> advantage to them were gains in economy, and when concidered vs. the added
> complexity and running problems they weren't worth it. The Big Boys were
> built between 1941 and 1944, by the way.
>
> As to the phase relationship's effect on power output, I am not enough of an
> ME to figure that one out. I do know that the phase relationship could effect
> the handling characteristics of multi-engine locomotive. The B&O's George
> Emerson 4-4-4-4 duplex, which had two sets of four drivers each driven by
> their own pair of cylinders, in it's initial configuration rode very rough
> (and was very hard on the track) when the two sets of drivers were in phase
> or close to it. Since the reciprocating forces (generated by siderods) would
> combine in this case, the final solution was to turn an inch off the diameter
> of one engine's tires so that they continually moved into and out of phase
> with the other. Haven't heard of this being such a problem on an articulated
> locomotive, and maybe this is less serious in those cases. OK, have at me...
> --
> Rick Vera-Burgos (work:Ric...@e-mail.com, home:Ric...@msn.com)
> Div. Supt. B&O Cumberland Division East End (under construction)
> Novi, Michigan
I think that the Brits with the GW (and others) experimented with 4-cylinder
locomotives, all cranks on the same axle, with the compound cranks 90 degrees
offset from the HP cranks, and gained a lot in smooth running, at (of course)
the expense of increased complexity.
Dan Mickey
ernf...@primenet.com
In <5cjk0e$t...@lastactionhero.rs.itd.umich.edu>, john cooley <john....@umich.edu> writes:
>Ah-- but I *do* have an idea of what a can of worms I opened-- I just
>want to see what the pundits have to say!
>
>mallets, so any problems with "phase" relationships between the separate
>engines would, I think have to do with any rotating or lateral forces
>exerted by one engine on the other or on the entire locomotive. I suppose
>those *should* all be balanced out, but then again. . . .
They were not mallets.
I was told by a railroader that the engines on articulateds tended to get in step
with each other and also in phase so that the exhaust sounded like that of a
single two-cylinder engine. The weird ones were the 3-cyllinder jobbies, they
could never get in phase.
ernie fisch
Mr. Bruce C. Sherman
> The Henry Ford Museum has a C&O Allegheny that they tout as the
"largest and
> most powerful steam locomotive ever built."
>
firebox,
> while the Big Boy is longer, and has larger cylinders. Not sure
about peak
> horsepower, but it's probably possible to carefully pick a speed
where one or
> the other might have the higher horsepower.
>
on
> straight, dry, level track?
>
>
Since it was so large people just figured it was the strongest. I do
not know the strongest, might be the Allegheny you saw.
Bruce from Bklyn,NY
1/28/97 5:27 PM
Mr. Bruce C. Sherman
Rick Vera-Burgos
john cooley wrote:
>
> Ah-- but I *do* have an idea of what a can of worms I opened-- I just
> want to see what the pundits have to say!
>
Well, we'll see how many pundits chime in - they may all be tired of it. I
seem to recall that this subject was hashed (and rehashed, and re-rehashed)
out here just a few months ago.
> I'm also (almost but could be wrong) 100% sure that the Big Boys were not
> mallets, so any problems with "phase" relationships between the separate
> engines would, I think have to do with any rotating or lateral forces
> exerted by one engine on the other or on the entire locomotive. I suppose
> those *should* all be balanced out, but then again. . . .
The Big Boy was definitely not a compound engine. I am not aware of a
roger traviss
ernf...@primenet.com wrote:
: I was told by a railroader that the engines on articulateds tended to get in step
: with each other and also in phase so that the exhaust sounded like that of a
: single two-cylinder engine. The weird ones were the 3-cyllinder jobbies, they
: could never get in phase.
And the other interesting thing is, nobody knows why or how they get into
sync. They just do. Even in one of the engines slips.
Cheers
Roger Traviss
From rainy and foggy Victoria, BC Canada
roger traviss
Daniel A. Mickey (dmic...@ix.netcom.com) wrote:
: I think that the Brits with the GW (and others) experimented with 4-cylinder
: locomotives, all cranks on the same axle, with the compound cranks 90 degrees
: offset from the HP cranks, and gained a lot in smooth running, at (of course)
: the expense of increased complexity.
"Experimented"? Heck, the railways in the UK had hundreds of 4 cyclinder
locomotives.
Janos ERO
Daniel A. Mickey wrote:
>
> I think that the Brits with the GW (and others) experimented with 4-cylinder
> locomotives, all cranks on the same axle, with the compound cranks 90 degrees
> offset from the HP cranks, and gained a lot in smooth running, at (of course)
> the expense of increased complexity.
The famous french engines built by Andre Chapelon were deGlehn compounds. The
high pressure cylinders were located outside of the frame, and was connected to
the second driver, while the low pressure cylinders were inside the frame and
were connected to the first drivers. This arrangement gives very smooth operation
and reduces the connecting rod forces. The Chapelon Pacifics were probably the
most effective among the steam engines but they were very complicated to operate
and expensive to maintain.
Janos Ero
David J. Dewey
As I have heard, although there is no connection in a simple articulated,
for some reason they would become syncronized while running.
(vibrations???) I wasn't there to witness it!
Steamcerely,
David Dewey
Moritz Gretzschel
Janos ERO <Jano...@cern.ch> wrote:
> When dragging the rear engine had more weight, thus
> the front engine easier slipped. The engineer should keep care of this and
> separately reduce the front engine pressure. With the "true-Mallets" this was a
> smaller problem: when the front engine slipped, it consumed too much steam from
> the rear engine, thus its pressure automatically dropped.
NO, on the contrary, this was a MUCH BIGGER problem with "true-Mallets":
When the low-pressure-engine (usually the front engine) slips,
the pressure in the manifold between the two engines drops
and the low-pressure engine slows down (so far you ar right).
But watch the high-pressure-engine then:
It normally works with the difference between the boiler-pressure
and the input pressure of the low-pressure engine. If the
pressure between the two engines drops, the difference to the
boiler pressure gets much bigger, and the torque of
the high-pressure-engine rises dramatically.
Under heavy conditions, when the whole problem ususally occurs,
this causes the high-pressure-engine to slip, too.
Meanwhile the low-pressure engine runs normally again, and
therefore the slipping high-pressure-engine produces too much
steam. So the pressure in the connecting manifold steeply rises.
The high-pressure-engine gets grip again, and the
low-pressure-engine starts to slip again, and so on, and so on....
Once these self-excitated oscillations have started,
they are very hard to stop without major loss of traction force.
That is, for example, the reason why the heaviest german
tender locomotive, the class 96, used for steep ramps in Bavaria,
never could put into practice its full friction weight.
Moritz
--
Moritz Gretzschel Moritz.G...@dlr.de
http://www.op.dlr.de/FF-DR/dr_fs/staff/gretzschel/gretzschel.html
Deutsche Forschungsanstalt fuer Luft- und Raumfahrt
Abteilung Fahrzeug-Systemdynamik
Paul Tackowiak
> The Henry Ford Museum has a C&O Allegheny that they tout as the >"largest and most powerful steam locomotive ever built."
> If my figures are correct, the Allegheny is heavier and has a larger >firebox, while the Big Boy is longer, and has larger cylinders. Not >sure about peak horsepower, but it's probably possible to carefully pick >a speed where one or the other might have the higher horsepower.
>
> So, to make a simple comparison, which one could start a longer train >on straight, dry, level track?
>
train' we mean heaviest, I'm immagine you'll have to include the DM&I
Yellowstone and probably a few others in this comparison, but keep in
mind that engines like the Big Boy were designed for peak performance at
a particular speed with a particular load. They weren't simply the
biggest engine the engineers could create. Starting tractive effort does
also not equal peak horsepower so the engine that can start the heaviest
train rolling may not be the most powerful in terms of horsepower. In
fact it might prove to be a less heralded compound mallet that never
went more than 25 mph. (Please, let's leave the triple articultes out of
this since they proved unworkable.)
But, as I said, if this thread continues you'll hear more about this
then you ever cared to know.
PT
John Cooley
Thanks for the information about the engines on an articulated getting in sync.
Sorry if the issue of "biggest" is one of those that just won't go away-- I
was "off line" for a few months, and that must have been when this thing last
came up-- but it at least suggests that the folks at Henry Ford are vastly
oversimplifying things in their displays!
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Janos ERO
David J. Dewey wrote:
>
> As I have heard, although there is no connection in a simple articulated,
> for some reason they would become syncronized while running.
> (vibrations???) I wasn't there to witness it!
Interesting phenomen, and I can imagine this is true. Probably only at
higher speeds, when the unbalanced drivers start to vibrate the whole
structure, generating oscillations for the entire spring- and equalization
system. The slipping tendency is not homogenous, it is connected to the
drivers' position anyway. Thus the front and rear engines can shake each
others to the same position. AFAIK -all- steam engines had a certain
slipping when they pulled most, some 1-2 mph.
Moritz Gretzschel wrote:
>
>
>When the low-pressure-engine (usually the front engine) slips,
>the pressure in the manifold between the two engines drops
>and the low-pressure engine slows down (so far you ar right).
>But watch the high-pressure-engine then:
>It normally works with the difference between the boiler-pressure
>and the input pressure of the low-pressure engine. <snip>
>The high-pressure-engine gets grip again, and the
>low-pressure-engine starts to slip again, and so on, and so on....
>Once these self-excitated oscillations have started,
>they are very hard to stop without major loss of traction force.
>That is, for example, the reason why the heaviest german
>tender locomotive, the class 96, used for steep ramps in Bavaria,
>never could put into practice its full friction weight.
Interesting stuff, quite plausible. BTW Hungary operated many Mallets before
the WW1, quite big ones (Class 601), but I never heard any reports about the
above behavior. Probably it is very engine-dependent. Anyway I don't fully
understand: a steam reservoir between the high and low pressure engines
probably would help. (AFAIK some compound engines were reservoir equipped.)
Janos Ero
Craig A. & Paula R. Eddy
john cooley <john....@umich.edu> wrote in article
<5cjk0e$t...@lastactionhero.rs.itd.umich.edu>...
> Ah-- but I *do* have an idea of what a can of worms I opened-- I just
> want to see what the pundits have to say!
>
> I'm also (almost but could be wrong) 100% sure that the Big Boys were not
> mallets, so any problems with "phase" relationships between the separate
> engines would, I think have to do with any rotating or lateral forces
> exerted by one engine on the other or on the entire locomotive. I suppose
> those *should* all be balanced out, but then again. . . .
>
Correct. The Big Boys were not true Mallets. The Mallet had a low
pressure front driver and a high pressure rear driver. The Big Boy had
equal (as equal as modern science could make them) driver pressures.
James D Thompson
Rick Vera-Burgos (Ric...@msn.com) wrote:
: The Big Boy was definitely not a compound engine. I am not aware of a
: compound steam engine built for use in this country since 1920. The only
: advantage to them were gains in economy, and when concidered vs. the added
: complexity and running problems they weren't worth it. The Big Boys were
: built between 1941 and 1944, by the way.
Hang on a minute there. Norfolk and Western built a boatload of Mallet
compounds after 1920, and a number of other roads got Mallets after WW1 as
well. The simple articulated did become more common in the 1920s, but the
compound never went away. In fact, the last articulated built for use in the
US was an N&W Y6b compound 2-8-8-2 in 1952.
David Thompson
bu...@kuhub.cc.ukans.edu
In article <5cm10d$f...@usenetz1.news.prodigy.com>, PTJ...@prodigy.com (Mr. Bruce C. Sherman) writes:
>> The Henry Ford Museum has a C&O Allegheny that they tout as the
> "largest and
>> most powerful steam locomotive ever built."
>>
>> If my figures are correct, the Allegheny is heavier and has a larger
> firebox,
>> while the Big Boy is longer, and has larger cylinders. Not sure
> about peak
>> horsepower, but it's probably possible to carefully pick a speed
> where one or
>> the other might have the higher horsepower.
>>
>> So, to make a simple comparison, which one could start a longer train
> on
>> straight, dry, level track?
>>
>>
> Since it was so large people just figured it was the strongest. I do
> not know the strongest, might be the Allegheny you saw.
> Bruce from Bklyn,NY
> 1/28/97 5:27 PM
>
>
Big Boy could run at speeds up to 80 MPH. In fact, power and speed were both
important. I have read that the combination was one of the compelling reasons
for designing both the Challenger and Boy. Starting might not have been as
important as pulling power at speed over the mountains west of Cheyene.
How would the Big Boy rate if you considered both speed and power?
Jim Budde
K SF & P RR
Kurt Greske
I think one thing that is being missed here ( at least as far
back as my list server goes here ) is the difference between horsepower
and tractive force. Just like an automobile engine has both a
horsepower peak and a torque peak in its ratings, a steam locomotive has
both a tractive force rating, at very low speed; and a horsepower
rating, hopefully somewhere near normal operating speed. It is VERY
common for a high speed passenger locomotive like a 6000 horsepower New
York Central S-1 Niagara to have a much lower tractive force rating than
a drag freight locomotive like the ( about ) 5500 horsepower Norfolk &
Western Y-6B. In this case, it is obvious of course, but when comparing
locomotives like Big Boys, Alleghenys, and Yellowstones, it isn't quite
so clear cut.
The really nice thing about the Big Boy is that first its design
was very nicely optimized for what it was intended to do; and secondly,
it was used in a manner that was consistent with its design
optimization. As such, it provided really spectacular performance and,
in my opinion, became the "sun god" of all steam locomotives. The
Allegheny is something of an enigma. It had a very large boiler and a
lot of heating surface ( which is indicative of an intent for it to be a
high horsepower locomotive ), but the Big Boy had a greater firebox
grate area ( partly because it was intended to burn Wyoming coal which
has a lower heating value than West Virginia coal ). Still, they could
have used the general design of the firebox on the Big Boys and
Challengers and kept a four wheel trailing truck. Of course, now it
would have too high an axle loading, so you should add two more driving
axles. And if you want to make use of all that horsepower ( THAT'S why
you bought it, isn't it! ), you put on a four wheel pilot truck and use
it in high speed time freight service, NOT for pulling coal drags! It
begins to look like a Big Boy designed for east coast high heating value
coal, doesn't it! THAT could have been a really spectacular locomotive,
but that isn't what Lima built or how the C&O and Virginian used them.
Considering the service for which both the C&O and Virginian used them,
they would have been better off with something more like the N&W Y-6B.
I think that some people from Lima wanted to push their high horsepower
and six wheel trailing truck ideas and took advantage of the first
opportunity that was available -- even if it was a misapplication. The
inevitable results were much less than desirable.
Kurt
Kurt Greske
Dear John,
The Big Boy, ten times out of ten! The Allegheny was a misdesigned
locomotive. The boiler was spectacular but the engine wasn't. Well,
sort of spectacular -- it didn't even have 300 psi boiler pressure like
the Big Boy had. Its 6 wheel trailing truck placed too much load on
nonproductive axles.
The twin stack on the Big Boy was just two stacks in parallel from a
common header. The exaust from both engines fed into that header and
was exausted out of both stacks at the same time.
Yes the two engines were completely independent and could change phase
relationship. Only the front engine swiveled, the back engine on all
articulateds was rigidly attached to the boiler -- that is why it is a
4-8-8-4 NOT a 4-8+8-4 like Trains' Dave Morgan got a bee in his bonnet
about near the end of his life!! The phase relationship was constantly
changing as the drivers would creep on the rail under load. This really
didn't matter because the cutoff was set long on starting. Once it got
up to speed, it was really just a matter of pushing with enough pulses
to keep the train moving. In theory, yes when the two engines were
exactly in phase, it would have its peak tractive force but in practice,
it didn't matter.
If you are interested in more information write me.
Kurt
Douglas Menke
I'll take you one further, David. According to the book "Steam, Steel,
and Stars" by O. Winston Link (we all know who he is) the last regular
revenue run on a class A railroad was a Y6b on May 2nd (or 3rd), 1960
for the N&W. I don't have the book here in front of me right now, or I
could give you the loco number
Doug
Janos ERO
Daniel A. Mickey wrote:
> A lot of Mallet compound engines were converted into the two simple engine
> configuration to avoid the problem of trying to keep one stalled engine from
> stopping steam flow through both sets of engines. This was a major
> shortcoming of the Mallet type.
I think this is not the case. The ancient designers weren't so silly to build
a locomotive which sometimes cannot start! -All- compound engines had a
"starter" equipment, which allowed the engineer to redirect high pressure
steam into the low pressure cylinders. The traction force was bigger this way,
also a benefit when starting. This procedure required much more steam however,
thus the engineer should have closed the starter soon after the train started
to move. In some later French compound engines this happened automatically.
The compound engines were particularly popular in the age before inventing the
super heater (Schmidt, 1907). They were much more effective than the simple
expansion engines. Equipped with super heater they still remained more
effective, but not in an extent which could justify the higher purchase and
maintenance costs. They also required better trained engineers.
The single expansion articulated engines were introduced later, as there were
serious problems to implement a large diameter flexible high pressure tubing.
Janos Ero
Rich Weyand
In article <32F1FA...@sen.wiu.edu> Douglas Menke <dou...@sen.wiu.edu> writes:
>From: Douglas Menke <dou...@sen.wiu.edu>
>Subject: Re: [proto] Big Boys and articulated steamers--question
>Date: Fri, 31 Jan 1997 07:59:36 -0600
>James D Thompson wrote:
>>
>> Rick Vera-Burgos (Ric...@msn.com) wrote:
>>
>> : The Big Boy was definitely not a compound engine. I am not aware of a
>> : compound steam engine built for use in this country since 1920. The only
>> : advantage to them were gains in economy, and when concidered vs. the added
>> : complexity and running problems they weren't worth it. The Big Boys were
>> : built between 1941 and 1944, by the way.
>>
>> Hang on a minute there. Norfolk and Western built a boatload of Mallet
>> compounds after 1920, and a number of other roads got Mallets after WW1 as
>> well. The simple articulated did become more common in the 1920s, but the
>> compound never went away. In fact, the last articulated built for use in the
>> US was an N&W Y6b compound 2-8-8-2 in 1952.
>I'll take you one further, David. According to the book "Steam, Steel,
>and Stars" by O. Winston Link (we all know who he is) the last regular
>revenue run on a class A railroad was a Y6b on May 2nd (or 3rd), 1960
>for the N&W. I don't have the book here in front of me right now, or I
>could give you the loco number
Y6b #2190, and it was May 6, 1960. The last steam on the N&W was S1a
(0-8-0 switcher) number 291, which dropped her fires the next morning,
May 7, 1960.
Rich Weyand | _______ ___,---. ---+_______:_ |Rich Weyand
Weyand Associates| |_N_&_W_| |_N_&_W_| |__|________|_ |TracTronics
Comm Consultants | ooo ooo ~ ooo ooo ~ oOOOO- OOOO=o\ |Model RR Electronics
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Rich Weyand
>Power was undoubtedly more important than just speed, but I have heard that the
>Big Boy could run at speeds up to 80 MPH. In fact, power and speed were both
>important. I have read that the combination was one of the compelling reasons
>for designing both the Challenger and Boy. Starting might not have been as
>important as pulling power at speed over the mountains west of Cheyene.
>How would the Big Boy rate if you considered both speed and power?
Big Boy was built to run the fruit trains of the PFE over Wasatch and
Sherman Hills with a design speed of 25 mph uphill and 50 mph downhill.
Given that mission, maintaining those speeds was very important. Big
Boy HP was 5600 at 25 mph, and peaked at 6000 HP between 30 and 42 mph.
Both the Big Boy and Challenger could run light at speeds to 80 mph,
and I myself have chased Challenger 3985 at the maximum signal speed
available of 70 mph and she wasn't even trying. (Chased it in a plane;
I'm not crazy.)
The Allegheny initially tested at 7498 HP, but at speeds above 40 mph.
Bear in mind that late steam-era locomotives were built for specific
needs, with the HP, tractive effort and speed well specified for the
mission. Comparing the Big Boy, the Allegheny, and the N&W's Y and A
class machines is very instructive at just how targeted these machines
were, and how well they met their design goals. While the Allegheny
had the superior HP, it was developed at a high enough speed, and at
such a cost and weight penalty compared to the UP and N&W engines, that
the latter should probably be considered more economically successful.
The Allegheny wasn't an open field runner, like the BB and the A, and
it didn't have the incredible starting tractive effort and low speed
HP of the Y, so it was neither a mountain slugger or a fast freight
engine.
Daniel A. Mickey
Douglas Menke wrote:
>
> James D Thompson wrote:
> >
> > Rick Vera-Burgos (Ric...@msn.com) wrote:
> >
> > : The Big Boy was definitely not a compound engine. I am not aware of a
> > : compound steam engine built for use in this country since 1920. The only
> > : advantage to them were gains in economy, and when concidered vs. the added
> > : complexity and running problems they weren't worth it. The Big Boys were
> > : built between 1941 and 1944, by the way.
> >
> > Hang on a minute there. Norfolk and Western built a boatload of Mallet
> > compounds after 1920, and a number of other roads got Mallets after WW1 as
> > well. The simple articulated did become more common in the 1920s, but the
> > compound never went away. In fact, the last articulated built for use in the
> > US was an N&W Y6b compound 2-8-8-2 in 1952.
> >
> >
>
> I'll take you one further, David. According to the book "Steam, Steel,
> and Stars" by O. Winston Link (we all know who he is) the last regular
> revenue run on a class A railroad was a Y6b on May 2nd (or 3rd), 1960
> for the N&W. I don't have the book here in front of me right now, or I
> could give you the loco number
>
Model Railroader had a write-up on Challengers in their Jan 1995 issue if you
can get it. Included was a photo of a restored Challenger enroute to an
excursion event, pulling 28 5-unit stack cars. It probably displaced about 5
GPs.
Dan Mickey
Paul Tackowiak
I don't know why this only just appeared on my machine today, 3 days
late, but...
Rick Vera-Burgos wrote:
: The Big Boy was definitely not a compound engine. I am not aware of a
: compound steam engine built for use in this country since 1920. The
only
: advantage to them were gains in economy, and when concidered vs. the
added
: complexity and running problems they weren't worth it. The Big Boys
were
: built between 1941 and 1944, by the way.
As David Thompson correctly pointed out the N&W disproved this by
developing both the compound Y6B and the single expansion A
simultaneously right up to the final days of mainline steam operation in
this country. Both engines were unsurpased as the highest level of
technical development ever achieved for steam locomotives. The Y6B
demonstrated incredible thermal effeciency and tractive effort for a
steam engine while the A may have been the very best high-horsepower
steam engine ever built. The Big Boy and Allegheny were considerably
larger, but the A could do nearly the same work but at lower cost.
Interesting how we are once again about to see 6000 HP behemoths moving
mountains over rails. Any one know what the tractive effort of one of
these monsters will be?
PT
Kurt Greske
You are going gaga over N&W designs. They used spoked wheels and
alligator crossheads. There was a LOT to be improved in them!
Kurt
Kurt Greske
The real purpose of compounding was to cut the pressure drop ( and
consequently the temperature drop which is the IMPORTANT thing ) across
the cylinder from the inlet to the exhaust conditions. The steam cools
as it does work against the piston and that cools the cylinder and steam
passages when the steam is exhausted. Then new steam coming from the
boiler is cooled by the cool steam passages and cylinder walls. This
causes the new steam to lose energy even before it gets the chance to do
work against the piston. Compounding greatly lessens this effect and
makes the engine more efficient.
NOW, superheating the steam does much the same thing and therefore there
was much less need for compounding after the invention of the
superheater. Most railroads abandoned compounding because it has other
problems like the fact that the low pressure cylinders don't do much
until the engine gets going. The N&W solved this problem with a
regulator system that allowed boiler steam to be dropped in pressure and
used in the low pressure cylinder. It is needlessly complex. A simple
( single expansion ) articulated is more powerful and faster and much
less complicated. So it is more reliable, and reliability is the name
of the game in locomotive design. IOW, it is built to do work not sit
in the repair shop. N&W themselves considered a simple articulated as
the next step had that not been interupted by diesels.
This is a shortend and symplified explanation, if you are interested in
more details write me.
Kurt
Janos ERO
Kurt Greske wrote:
>
> You are going gaga over N&W designs. They used spoked wheels and
> alligator crossheads. There was a LOT to be improved in them!
Kurt, slower, please. IMO none of the mentioned items were obsolete ever.
Many late steam engines used alligator crosshead. I don't know any good
argument which would prove that a single guided crosshead is superior.
The spoked wheel is rather a technologic question. For instance the Swiss
electric Re6/6, probably the most powerful single locomotive in the world
(~10500HP) has spoked wheels - today. But probably the Swiss locomotive
industry is anyway inferior... :-)
Janos Ero
Kurt Greske
I can list SEVERAL reasons why alligator crossheads are inferior:
1. The lower guide makes it VERY hard to service the crankpin that is
hidden behind it.
2. The lubricant gets washed off of the lower guide by the steam.
3. The lower guide is much more exposed to dirt.
4. The lower guide and carrier sticks out and causes clearance problems.
5. The combined bearing surface area of the alligator guides is
significantly less than the combined bearing surface area of the
multiple bearing guides.
6. The reciprocating mass if the alligator crosshead is much greater
than the reciprocating mass of the multiple bearing crosshead.
7. The multiple bearing guide is much easier to allign.
Now for spoked wheels:
1. The MAJOR one is that the spokes are troubled with cracking problems
that any of the various disk drivers eliminated. This can be very
dangerous and lead to catastrophic failure at high speed!
2. Sort of related to the above but the various disk wheels were MUCH
stronger.
3. There isn't as much volume available for balancing weight.
Sorry, I'm a mechanical engineer, not only is this a hobby with me but
it is my business!
It is said that the N&W could cast their own spoked wheels but not any
of the various disk wheels, so THAT is why they stuck to them when it
didn't make sense to do so. Europe is a VERY lousy example to follow
since most locomotives were "toys" there.
Howard C. Swanson
Kurt,
I agree with you. The Alleghenies were designed for high speed coal
drag service (I know that this sounds like a contradiction). If the
C&O had used them correctly, they would have used them on a fairly
flat straight piece of railroad. The N&W designed and used the A's in
this type of service between Williamson and Columbus. I believe that
the Virginian used their Alleghenies between Roanoke (end of the
electrification) and Norfolk. This should have been a good route to
use the Alleghenies on.
The problem with comparing steam locomotive is that to be successful
they had to be "designed" for a specific terrritory. The N&W did one
of the better jobs of matching power to the territory.
Howard C. Swanson
Kurt Greske
On the chance that you may not be familiar with American steam
locomotive engineering practices, I should point out that the crosshead
guide that looks like a single bearing "Laird" or "Dean" guide that was
used on virtually all modern American steam locomotives is really a
"multiple bearing guide". On an HO gauge model, it is hard to tell the
difference. Anyway, the multiple bearing guide was the newest of the
lot, and has several advantages that I listed previously. It has
several parallel guide surfaces that are integral with a single
structural guide bar. The fact that the guide surfaces form a mostly
closed box tends to keep them clean and helps keep the lubricating oil
from being washed off by steam and rain.
Also, drive wheel centers like the "Boxpok" and "Baldwin Disc" are
really variations on the disc design even though they may appear to have
"spokes" on a model locomotive.
Please feel free to write back, I enjoy talking about steam locomotive
design very much.
Kurt
F. DABNEY
Kurt Greske (kurt_...@omail.eee.org) wrote:
: You are going gaga over N&W designs. They used spoked wheels and
: alligator crossheads. There was a LOT to be improved in them!
True, but they were still among the last big steam in mainline service,
and like a lot of other survivors, outlasted a lot of more sophisticated
designs. If the N&W could have gotten parts, they may well have lasted
yet another decade. The N&W did /not/ like abandoning coal power.
Fred D.
Watching the action from BNSF MP 1112, El Paso sub
Kurt Greske
Dear Fred,
Oh yes, I agree with you. I like the N&W locomotives very much too. I
just don't think that they are the "ultimate design" like some people do
-- that doesn't give due credit to a LOT of other very good designs.
I've already mentioned that I thought the Y-6B would have been better
for the C&O than the Allegheny was. A Class J could put out some VERY
impressive performance on a 1.2 percent grade with a passenger train.
Ditto the A with a 14,000 ton coal train in the Scioto division. And of
course their servicing facilities and service design philosophy were
second to none. If everybody else had thought like that, steam would
probably still be around today.
Kurt
Paul Tackowiak
Kurt Greske (kurt_...@omail.eee.org) wrote:
: You are going gaga over N&W designs. They used spoked wheels and
: alligator crossheads. There was a LOT to be improved in them!
Please name me a steam engine which surpassed either the Y6B or A. They
were designed years after Alco or Baldwin stopped making articulates and
were naturally going to incorporate some of the last leasons learned
regarding that type of motive power. No steam engine was perfect - if so
it would still be running - but it's a no brainer that last N&W designs
were the most advanced. N&W had a vested interest in keeping coal as a
fuel supply and spared no effort in getting the most from that resource
for as long as it made economic sense.
What's interesting is that the A and Y6B were so good that they both
held their own against a 4 unit EMD demonstrator in 16,000 ton revenue
tests over the N&W mainline. As Fred Dabney said it was only the cost of
replacement parts and repairs that pushed the big engines aside as soon
(1960!) as they did. Quite a tribute to the in-house engineering staff
of a RR.
PT
Rick Vera-Burgos
I stand thoroughly and completely corrected on my "none after 1920s comment".
I conveniently forgot about the N&W. I can only say that you should note that
my exact words included "I am not aware of". That includes "momentarily not
aware of"! Sorry to all the N&W guys out there.
Now that I've assuaged that slight, I can't help but toss more gasoline on
the fire. Although I admit I am not a steam locomotive design expert, based
on what I *do* know I tend to agree with Mr. Greske, that N&W locos weren't
necessarily the greatest designs. I think there were lots of modern
implementations by Baldwin and Lima during the 40's that were as good or
better, just too late to be widely accepted and therefore completely
developed. Not that the N&W designs were particularly *inferior*, but despite
the steam fan that I am, I tend to view history without my rose colored
glasses on.
I also disagree that their steam program lasted as long as it did because of
the superiority of there design - economic and locational advantages allowed
their management to be just plain stubborn. Thus, there development
department remained well funded and there motive power people were
continually encouraged to hang on to steam when the rest of the North
American major roads had long since given up on it, dooming Baldwin, Lima and
the rest in the process.
I guess what I'm saying is that N&W steam development continued 10 years
after nearly everyone else quit altogether. So, of course they managed to
improve performance of their last generations beyond locomotives build a
decade before. I think, though, that economies of scale prevented them from
coming up with really revolutionary improvements. After all, their
development was sold to themselves and a couple other roads; Baldwin and Lima
built for 100's. If I'm wrong here, please quote me some major design
breakthroughs they came up with after 1945.
--
Rick Vera-Burgos (work:Ric...@e-mail.com, home:Ric...@msn.com)
Div. Supt. B&O Cumberland Division East End (under construction)
Who cried when he read the 611 last run story in Trains
Novi, Michigan
A R BREEN
In article <Pine.HPP.3.95.970129...@steroid.ecst.csuchico.edu>,
David J. Dewey <djd...@ecst.csuchico.edu> wrote:
>As I have heard, although there is no connection in a simple articulated,
>for some reason they would become syncronized while running.
>(vibrations???) I wasn't there to witness it!
I seem to recall a discussion on this in Railway Magazine, circa 1973ish.
The explanation seems to lie in the exhaust system, with the exhaust of
the 'puff' from one engine unit entraining (no pun intended!) the exhaust
from the other unit. The engine units themselves don't come into true
synchronisation, but because of the exhaust effects, their exhaust beats do.
I've not seen this happen on the big beasts though, and the Fairlies on the
Ffestiniog (fairly obviously..) don't have this property.
| Andy Breen | Adran Ffiseg/Physics Department, UW/PC Aberystwyth |
| a...@aber.ac.uk | http://www.aber.ac.uk/~azb Tel: (44) 01970 621907 |
"Onwards. Things to do. People to damage." (Mr Croup, in 'Neverwhere')
Rich Weyand
>Now that I've assuaged that slight, I can't help but toss more gasoline on
>the fire. Although I admit I am not a steam locomotive design expert, based
>on what I *do* know I tend to agree with Mr. Greske, that N&W locos weren't
>necessarily the greatest designs. I think there were lots of modern
>implementations by Baldwin and Lima during the 40's that were as good or
>better, just too late to be widely accepted and therefore completely
>developed. Not that the N&W designs were particularly *inferior*, but despite
>the steam fan that I am, I tend to view history without my rose colored
>glasses on.
Harumph.
You ask for major design breakthroughs after 1945, but steam locomotive
design was unlikely to provide major design breakthroughs on the
existing platforms that late in the development history. Major break-
throughs in a mature technology often require 'drop back and punt'
approaches that rethink basic concepts. Jawn Henry certainly qualifies
here. Although not a mature design, the prototype displayed some
interesting characteristics (including its absolutely incredible TE
of 300,000 pounds) in addition to its obvious flaws (low speed and
extreme sensitivity to water quality among them).
But look at the last group of N&W designs, most of which were drawn
up in the late 30s:
The J, with 80,000 pounds TE had more TE than any other Northern.
Top speed in service was supposed to be 80 mph, but they had to move
the speedometers closer to the engineer's window after a couple of
engineers rolled them over on curves doing better than 100. The
locomotive was so smooth, with no hunt or pound, that they simply
didn't realize how fast they were going. The Pennsy tested them to
110 mph, but built the T-1s instead.
The A, with 6300 HP and a service speed of 80 mph, was about as good a
hill country runner as was built. Cheap, light, powerful, and fast,
she was good for flatland running with heavy freights and manifest
trains through the mountains.
The Y, with the highest TE of any sixteen driver locomotive (only the
2-10-10-2 had more) was also efficient at speed with the simpling
valve off. Top speed was as high as 50 mph, which is a pretty good
clip for a mountain slugger with that kind of tractive effort.
All of these locomotives had grate areas and heating surfaces which
would support continuous generation of rated HP at speed. Only the
Y with the simpling valve open couldn't keep steam up, and the
simpling valve was for starting trains, not continuous running.
Service numbers were unusually good. The N&W running only steam in
the first half of the 50's maintained better operating ratios than
every other US Class 1 railroad, diesels or no diesels. A 600 mile
run over the main line with any of these locomotives resulted in only
a 55 minute service turn before being ready for the return trip.
Compare this with early diesel service records. Some said that diesels
were designed to be MUed because, if you left with four, you had a
pretty good chance of two still running when you got to the end of
the run.
N&W switched to diesels late for a number of reasons: their customers
were coal mines and power plants and collieries, they owned their own
mines, and they had designed their way out of the steam locomotive
maintenance headaches. They didn't switch to diesels until the diesel
technology had matured enough to match up to the operating ratios and
service records they were used to with their existing power. Then
they switched over with a vengeance, completing the change in less than
five years.
Development in a mature technology is often a matter of small nits
and nats, not major breakthroughs. N&W ironed out the small nits and
nats, and produced exceptional motive power, because their design people
were closely in touch with the maintenance and operations people on
the railroad. They designed out the problems seen in the field, often
producing better power than most independent manufacturers did.
Terry Flynn
On Sun, 02 Feb 1997 13:17:11 -0800, Kurt Greske
<kurt_...@omail.eee.org> wrote:
>F. DABNEY wrote:
>>
>> Kurt Greske (kurt_...@omail.eee.org) wrote:
>> : You are going gaga over N&W designs. They used spoked wheels and
>> : alligator crossheads. There was a LOT to be improved in them!
>>
>> True, but they were still among the last big steam in mainline service,
>> and like a lot of other survivors, outlasted a lot of more sophisticated
>> designs. If the N&W could have gotten parts, they may well have lasted
>> yet another decade. The N&W did /not/ like abandoning coal power.
>>
>> Fred D.
>> Watching the action from BNSF MP 1112, El Paso sub
>
>Dear Fred,
>
> Oh yes, I agree with you. I like the N&W locomotives very much too. I
>just don't think that they are the "ultimate design" like some people do
>-- that doesn't give due credit to a LOT of other very good designs.
>I've already mentioned that I thought the Y-6B would have been better
>for the C&O than the Allegheny was. A Class J could put out some VERY
>impressive performance on a 1.2 percent grade with a passenger train.
>Ditto the A with a 14,000 ton coal train in the Scioto division. And of
>course their servicing facilities and service design philosophy were
>second to none. If everybody else had thought like that, steam would
>probably still be around today.
>
>Kurt
I would imagine the "ultimate design" would have been a Bayer-Garret
type articulated locomotive built to US loading gauge. As for largest
possible design there was a proposal (before WW2) for a combined
Garret Mallet machine, that would have had 4 sets of coupled drivers.
Imagin it, 2 big boys, back to back, with a big boiler joining them.
Good luck in building the model.
Terry Flynn.
Rich Weyand
>I would imagine the "ultimate design" would have been a Bayer-Garret
>type articulated locomotive built to US loading gauge. As for largest
>possible design there was a proposal (before WW2) for a combined
>Garret Mallet machine, that would have had 4 sets of coupled drivers.
>Imagin it, 2 big boys, back to back, with a big boiler joining them.
>Good luck in building the model.
I have toyed with building a 2-8-8-2+2-8-8-2 Beyer-Garrett-Mallet
from two Y6b chassis as a what-if project: What if the N&W decided
to build such a monster as a prototype, much like the Jawn Henry?
It would have had the same or better tractive effort than JH, but
it would have used all of their standard parts, had a much higher
speed and HP, and in general been a pulling monster with all of the
weight of the tender and the canteen (which they normally ran) all
on top of the drivers.
Of course, one motivation for building such a beast is that, with
the boiler to hold a lot of extra tungsten weight, it would be a
monster puller in N scale as well, not to mention being very
impressive, at some 2 feet long in N. :-)
Howard C. Swanson
>I have toyed with building a 2-8-8-2+2-8-8-2 Beyer-Garrett-Mallet
>from two Y6b chassis as a what-if project: What if the N&W decided
>to build such a monster as a prototype, much like the Jawn Henry?
>It would have had the same or better tractive effort than JH, but
>it would have used all of their standard parts, had a much higher
>speed and HP, and in general been a pulling monster with all of the
>weight of the tender and the canteen (which they normally ran) all
>on top of the drivers.
I would doubt that the N&W would have ever considered building a
Beyer-Garrett Y+Y because it would have too much drawbar pull. Too
much drawbar force leads to broken knuckles and bent underframes. I
was a management trainee in Bluefield when NS changed the standard
pusher consist from 3 SD-40-2's to 3 C-36-7's. One day we had three
hoopers in the yard at Bluefield whose underframes had been crushed.
Soon after that the pusher consists changed to 2 C-36-7's.
The reason why the N&W switched from steam to diesel later than
everyone else is that they had adopted "diesel" type maintenance
policies in the 1930's. These policies were; limited number of engine
types, standardized maintenance and careful measurement of locomotive
availability. The N&W did use some "inferior" technology but its
maintenance system either could compensate for the technology or
required the technology. The lubritoriums compensated for the poor
lubricating characteristics of the valve gear. I would guess that the
reason why the N&W kept using spoked drivers is that Roanoke Shops
could not cast drivers.
The MOST important thing to remember about N&W's motive power was that
it was an integral part of a complete motive power philosophy. No
other railroad reached the same level of fit between power,
maintenance and operation.
Howard C. Swanson
Darrell Boatwright
mike...@gmail.com
> I was sitting and looking at my plastic Big Boy model this weekend, and I came up with a question that applies to all similar articulated steamers:1. The Big Boy is, in a simplistic sense, two independent steam locomotives with a common boiler. 2. The action of these engines involves all kinds of lateral and rotating forces.3. Nothing keeps the two individual engines "synchronized"-- that is, nothing acts to keep both engines in the exact same phase of their cyles at the same time.4. Because the two engines can slip independently, the phase relationships can therefore vary.So here's the question:Is there a phase relationship between the two engines that leads to the greatest power output and the smoothest running, or does it just not matter? Another, specific Big Boy question:The Henry Ford Museum has a C&O Allegheny that they tout as the "largest and most powerful steam locomotive ever built." If my figures are correct, the Allegheny is heavier and has a larger firebox, while the Big Boy is longer, and has larger cylinders. Not sure about peak horsepower, but it's probably possible to carefully pick a speed where one or the other might have the higher horsepower.So, to make a simple comparison, which one could start a longer train on straight, dry, level track? _____________ ______________________________________ ============| | A00A\____[ ] [ ] [ ] | | [] [][][] [][][] =. \ ============| | \ ============| |___________...@umich.edu___________\ #(O)#(O)# | | #(O)#(O)#(O)# OOOOOOOOOOOOOOO #(O)#(O)#(O)# \
Kurt?, I am writing this 9-30-12. After reading about the various locomotives having more static power than another one,and being a skeptic after many years of employment where a management team can make figures say what they want, who were the individuals taking the measurement of the locos in question? I would suggest the east coast folks would not allow a loco from the dusty west to better one of their vaunted local locos. It doesn't take alot of thought to figure how to make one look better that another,ie., bleed off some of the boiler pressure, slightly apply the brakes,or...... I don't believe the BB was given a real chance against the east coast block of money and status. Hope you receive this and also hope your day is super.
Special Agent Melvin Purvis
> On Monday, January 27, 1997 1:00:00 AM UTC-7, John Cooley wrote:
> Kurt?, I am writing this 9-30-12. After reading about the various locomotives having more static power than another one,and being a skeptic after many years of employment where a management team can make figures say what they want, who were the individuals taking the measurement of the locos in question? I would suggest the east coast folks would not allow a loco from the dusty west to better one of their vaunted local locos. It doesn't take alot of thought to figure how to make one look better that another,ie., bleed off some of the boiler pressure, slightly apply the brakes,or...... I don't believe the BB was given a real chance against the east coast block of money and status. Hope you receive this and also hope your day is super.
square footage of the grate, having nothing to do with wheel
arrangment. Yes?
Roger Traviss
square footage of the grate, having nothing to do with wheel
arrangment. Yes?
Drawbar pull (lbs) times speed (mph) times 0.0027 equals horsepower.
But unlike an internal combustion engine where horsepower is constant,
horsepower on a steam loco is dependent on speed. So it's always varying.
You cannot state that Big Boy puts out 'X' horsepower like you can a diesel
locomotive.
You can only state that at 'Y' speed a Big Boy puts out 'X' horsepower.
--
Cheers.
Roger Traviss
Photos of the late HO scale GER: -
http://www.greateasternrailway.com
For more photos not in the above album and kitbashes etc..:-
http://s94.photobucket.com/albums/l99/rogertra/Great_Eastern/
Wolf K
> I believe that locomotive boiler horsepower is calculated from the
> square footage of the grate, having nothing to do with wheel
> arrangment. Yes?
>
>
> ------------------------------------------------
>
> Drawbar pull (lbs) times speed (mph) times 0.0027 equals horsepower.
>
> But unlike an internal combustion engine where horsepower is constant,
> horsepower on a steam loco is dependent on speed. So it's always varying.
"Horsepower" is the measure of the rate of using energy. (Or, looking at
it from the opposite end, the rate at which energy is supplied). It
varies with the load. The rated horsepower is simply the maximum
possible, assuming the engine is perfectly tuned, and running under
ideal (= test) conditions. Which isn't the case in Real Life, ever. ;-)
BTW, fuel consumption varies directly with the rate at which energy is used.
> You cannot state that Big Boy puts out 'X' horsepower like you can a
> diesel locomotive.
was more important. In practical terms, T.E. measures how much tonnage a
engine could haul. It too varies with speed. Since a train's drag varies
with speed, terrain, and track alignment, as well as weather, it was and
is not easy to decide how much locomotive to couple onto a train.
> You can only state that at 'Y' speed a Big Boy puts out 'X' horsepower.
used. A diesel locomotive hauling a 1000 ton train at 60mph will use
energy at a higher rate than hauling the same train at 30mph. Just like
a steam engine.
HTH
--
Best,
Wolf K
kirkwood40.blogspot.ca
Roger Traviss
> Same for a diesel locomotive. Horsepower is the rate at which energy is
> used. A diesel locomotive hauling a 1000 ton train at 60mph will use
> energy at a higher rate than hauling the same train at 30mph. Just like
> a steam engine.
Wolf K
> [Snip]
>
>> Same for a diesel locomotive. Horsepower is the rate at which energy
>> is used. A diesel locomotive hauling a 1000 ton train at 60mph will
>> use energy at a higher rate than hauling the same train at 30mph. Just
>> like a steam engine.
>
>
> Thanks for clarification Wolf.
>
>
Daniel A. Mitchell
the 'To' and 'Newsgroups' headers for details. ]]
On Tue, 9 Oct 2012 12:04:16 -0400, Wolf K wrote
(in article <4WXcs.30064$VC5....@fed15.iad>):
> On 08/10/2012 9:25 PM, Roger Traviss wrote:
>> [Snip]
>>
>>> Same for a diesel locomotive. Horsepower is the rate at which energy
>>> is used. A diesel locomotive hauling a 1000 ton train at 60mph will
>>> use energy at a higher rate than hauling the same train at 30mph. Just
>>> like a steam engine.
>>
>>
>> Thanks for clarification Wolf.
>>
>>
>
> You're welcome.
>
>
While a Diesel locomotive indeed does have a maximum horsepower, that of it's
Diesel engine at full output, it's not the same for a steam locomotive.
The maximum CONTINUOUS power ratings are arrived at in the same ways, but the
maximum PEAK horsepower can be VERY different for a steam loco (or an
electric loco).
With a Diesel, that's all there is, "there ain't no more".
The maximum a steamer can produce CONTINUOUSLY is that of the firebox ...
mostly a function of grate area and heating surface available.
HOWEVER, With a steamer, there can be a huge amount of STORED energy in the
superheated water in the boiler. For a short period a steam loco can produce
considerably MORE than it's continuous horsepower (by "consuming" this
water", at the eventual expense of reduced pressure in the boiler).
In this regard, a steam loco is more like an electric loco than a Diesel. An
electric loco has a maximum continuous horsepower, that can be as much as
tripled for a short while, at the expense of overheating it's electrical
systems. Such locos usually have multiple ratings ... continuous, one hour,
and some shorter term, like five minutes. The locos are designed to absorb a
certain amount of over heating, for a short while. At the expense of damaging
equipment the maximum horsepower can be temporarily huge.
An electric loco can continue to overpower itself until something either
breaks of melts. A steamer can only do so until the boiler pressure drops to
a level that effectively stops the overload, assuming nothing breaks in the
attempt.
If, however, enough steam is available (short term or continuosly), a steam
loco can literally destroy it's mechanism if too much power is applied. Even
the famous Gresley A4 Pacific that set the world record speed in Britain
suffered considerable damage in the (successful) attempt.
Both Diesels and steamers may encounter conditions that limit the power
available to pull the train. With a steamer, it's mostly a traction issue.
That much is true for Diesels also, though they usually have a better
adhesion factor. However, Diesels too have continuous and short-term
ratings, since at certain load and speed conditions, the traction motors
cannot absorb the full output of the Diesel engine for prolonged periods.
So, while a Diesel has a maximum power set by it's Diesel engine, it may well
have considerably LESS power available under many conditions.
They are ALL subject to a variety of conditions that limit their available
power at any one time. Still, steamers and electrics have less well defined
maximum power potential than a Diesel.
Dan Mitchell
==========
Christopher A. Lee
<danm...@tir.com> wrote:
>If, however, enough steam is available (short term or continuosly), a steam
>loco can literally destroy it's mechanism if too much power is applied. Even
>the famous Gresley A4 Pacific that set the world record speed in Britain
>suffered considerable damage in the (successful) attempt.
The Gresley inside big end bearing wasn't very good and overheating
was a known problem.
Nationalisation brought cross-fertilisation between the big four
companies, and one of the results was that the LNER pacifics were
fitted with the GWR inside big end and and that problem went away.
Wolf K
> [[ This message was both posted and mailed: see
> the 'To' and 'Newsgroups' headers for details. ]]
Well done, Daniel.
--
Best,
Wolf K
kirkw...@blogspot.ca