Can PRT ever approach the capacity of a high end metro system?
Mike C
are staggering: 700k passengers per weekday with a record of over 1M
during Obama's inauguration. They have up to 8-car trains, with each
car holding 175 crush load (70 seated, the rest standing). They run as
close to 3 minutes separation, though I suspect they could go even
lower (2 minutes?) if they needed to.
175 pas/veh * 8 veh/train * 30 trains/hr = 42000 passengers per hour
per line, maximum crush capacity. And they have 8 lines leading out of
the city center.
For PRT at 1-second headway and 1.5 passengers per vehicle, the
maximum capacity is 5400 passengers per hour. Eight lanes of PRT would
be required to match the crush capacity of each line of the metro, a
total of 64 (bidirectional) PRT lanes leading out of the city. For
platooned PRT vehicles, the number could go as high as 10-15k
passengers/hr, but you'd still need the equivalent of 24-30 PRT lines
leading out of the city to match the metro.
I can envision a time in the distant future when PRT could achieve
those kinds of capacities, but right now it's not even in the same
ballpark.
I raise this issue because I think the term "rail" gets muddied up in
discussions. When we say "rail" to someone in Manhattan or Washington,
they envision the high end systems they're used to, the ones that can
carry millions of passengers per day, and they scoff at the notion
that PRT could handle those capacities. And they believe that anyone
who suggests PRT could replace "rail" must be crazy.
But light rail is not metro rail. PRT's niche is where light rail
systems are being deployed, systems which carry one fifth the capacity
of a metro. We have to educate them on the differences, and show them
how PRT would replace one type of rail (light rail) and augment the
other (metro).
Mike C
gu...@systematica.net
Some lines of the Moscow metro carry 65000 passengers hour at peak. This is the throughput not the capacity. Trains travel at 90 seconds interval
Cheers
Luca
Le mail ti raggiungono ovunque con BlackBerry® from Vodafone!
-----Original Message-----
From: Mike C <mwil...@gmail.com>
Date: Sat, 27 Jun 2009 08:39:52
To: transport-innovators<transport-...@googlegroups.com>
Subject: [t-i] Can PRT ever approach the capacity of a high end metro system?
Walter Brewer
The famous trick used by mass transit promoters to emphasize peak capacity,
when the problem is getting enough riders and wasting capacity off peak.
Also ignoring the support needed by buses, bicycles, scooters, walkers,
strollers, you name it, to get people to their real destinations. PRT is
area coverage not just line.
It is apples and oranges to compare a sardine pack train with average seated
PRT. Expanding your example to PRT with 4 seated says about 3 guideways are
needed, and each take about 1/2 the ROW for the train. Let a couple stand in
thePRT also and you have a match. And no operators to pay in the process on
the trains or supporting buses, etc.
700K trips sounds like a lot but autos carry 20 million even for this very
concentrated community according to Texas Transportation Institute.
Walt Brewer
From: "Mike C" <mwil...@gmail.com>
To: "transport-innovators" <transport-...@googlegroups.com>
Sent: Saturday, June 27, 2009 11:39 AM
Subject: [t-i] Can PRT ever approach the capacity of a high end metro
system?
>
Mike C
The 700k number is actual riders per weekday, not peak capacity.
Regardless of the off-peak inefficiencies, this system carries a hell
of a lot of people into a small area of DC every day. I don't think an
existing PRT system could do that level of passenger movement.
Platooning and high guideway density might get you a little closer,
but the gap is still large when it comes to the raw people-moving
capability of a full metro.
That's why, even as we talk about PRT as a replacement for *light*
rail, we should stress that light rail is not the same as metro rail,
and that PRT's role in a city like DC would be to *complement* the
metros. Consider a PRT system in DC which parallels the metro lines.
In the peak hours, the metro would handle the bulk but the PRT would
serve as a high end alternative, priced 3-4 times the fare of a train
ride. Then, off peak, when the trains would be underutilized, PRT can
handle the full load at the regular train fare, and the trains can
shut down completely. That would be a good application of PRT in a
dense city.
But to imply that PRT can actually handle those kinds of loads today,
that just makes us look unrealistic. When we speak about PRT vs rail,
we need to stress the large capacity gap between light rail and
metros, and that we're referring to the former not the latter.
Mike
Michael Weidler
| I agree that PRT could not carry that many passengers on only 3 beams. Notice that Orange & Blue share track, Yellow & Green share track, and Red has it's own track equals 3 tracks. http://www.wmata.com/rail/maps/map.cfm An equivalent PRT system would more resemble the road network. --- On Sat, 6/27/09, Mike C <mwil...@gmail.com> wrote: |
Michael Weidler
| OK. I'll buy into that argument. |
--- On Sat, 6/27/09, Mike C <mwil...@gmail.com> wrote: |
|
|
Jack Slade
If I can find places where I need to move that many people in one direction, and I want to "crush" people, I can put 5 in each vehicle, and 1/2 second spacing (7200V per hr) = 36,000. Or I can build 8 lines, no crushing, at your 1 sec headway, and still be less cost than any subway or train system.
Don't be fooled by numbers. Toronto's TTC moves 1,000,000 on an average day, but that is spread over 18 hrs and 700 miles of streets and roads that are serviced.
There are 24,000,000 car trips as well, and the real money and real need is moving a good percentage of them, when gas fets high enough that a lot of them would want to leave cars at home. They don't do this yet, but a lot more would if TTC was not so inconvenient. The key to PRT is Convenience, and the figure I would hope for is 20%.
If I can do that, and make a 50cent profit from each, that is over 1/2 Bil per year.
Jack Slade |
Walter Brewer
The TTI data are also daily, although includes weekends. The entire mass
transit system for DC metro area including adjacent VA and MD is about 6
million passenger-miles. At average about 6 mile/trip that's about one
million boardings.That includes second and third transfers to get to real
destinations.
There is no doubt rail systems have high bulk capacity. That was their
origin as freight carriers. But again you can't ignore the rest of the
journey. Indeed DC Gov area is very concentrated so the feeder trips are
probably less than average.
As another point of comparison, there is just one 16 mile segment of San
Diego's LRT, to/from the Mexican border and downtown that operates nearly
full during peak hours. Its best hour is about 2,500 on boards, slightly
more than one freeway lane alongside.
Daily total is about 50,000. In fact this one original segment that
mesmerized LRT planners carries as many as the 50 or so miles added
throughout the area in 25 years.
I don't understand why you want to have PRT compete with LRT on a line haul
basis.
gary13
travel the same restricted routes, thus not carry the same capacity
over the same paths. PRT is much better than that...it delivers
people from A to B with A=home and B=destination. Show me a train
that does that.
gary
>
> - Show quoted text -
Jerry Schneider
>The 700k number is actual riders per weekday, not peak capacity.
>Regardless of the off-peak inefficiencies, this system carries a hell
>of a lot of people into a small area of DC every day. I don't think an
>existing PRT system could do that level of passenger movement.
>Platooning and high guideway density might get you a little closer,
>but the gap is still large when it comes to the raw people-moving
>capability of a full metro.
Remember that D.C. is very unusual in terms of the concentration
of employment in sector zero. There was an effort to decentralize
this employment decades ago but it was not carried out to any
significant degree.
>That's why, even as we talk about PRT as a replacement for *light*
>rail, we should stress that light rail is not the same as metro rail,
>and that PRT's role in a city like DC would be to *complement* the
>metros. Consider a PRT system in DC which parallels the metro lines.
>In the peak hours, the metro would handle the bulk but the PRT would
>serve as a high end alternative, priced 3-4 times the fare of a train
>ride. Then, off peak, when the trains would be underutilized, PRT can
>handle the full load at the regular train fare, and the trains can
>shut down completely. That would be a good application of PRT in a
>dense city.
Why do you think that this idea is preferable to the PRT as feeder/distributor
to the high capacity system? If the transfer is "seamless" like those in Canada
and the EU, is it really that big of a problem, especially when people get used
to it, like those in New Jersey now? Why this special effort to
provide a special
service to a small group of wealthy people (who often travel in limos
now) while
getting little or no use out of the expensive, depreciating, high
capacity system?
>But to imply that PRT can actually handle those kinds of loads today,
>that just makes us look unrealistic. When we speak about PRT vs rail,
>we need to stress the large capacity gap between light rail and
>metros, and that we're referring to the former not the latter.
Totally agree.
Mike C
On Jun 28, 12:35 pm, Jerry Schneider <j...@peak.org> wrote:
>
> Remember that D.C. is very unusual in terms of the concentration
> of employment in sector zero. There was an effort to decentralize
> this employment decades ago but it was not carried out to any
> significant degree.
>
> >That's why, even as we talk about PRT as a replacement for *light*
> >rail, we should stress that light rail is not the same as metro rail,
> >and that PRT's role in a city like DC would be to *complement* the
> >metros. Consider a PRT system in DC which parallels the metro lines.
> >In the peak hours, the metro would handle the bulk but the PRT would
> >serve as a high end alternative, priced 3-4 times the fare of a train
> >ride. Then, off peak, when the trains would be underutilized, PRT can
> >handle the full load at the regular train fare, and the trains can
> >shut down completely. That would be a good application of PRT in a
> >dense city.
>
> Why do you think that this idea is preferable to the PRT as feeder/distributor
> to the high capacity system? If the transfer is "seamless" like those in Canada
> and the EU, is it really that big of a problem, especially when people get used
> to it, like those in New Jersey now? Why this special effort to
> provide a special
> service to a small group of wealthy people (who often travel in limos
> now) while
> getting little or no use out of the expensive, depreciating, high
> capacity system?
a perk to the wealthy, but rather to provide a base level of service
for low demand periods so that trains don't have to run on schedule
deep into the night. This would make the metro more efficient as it
only needs to operate when it is most efficient and profitable, during
the peak times.
Charging higher fares for peak PRT would just be a way of managing the
demand during busy times. And the higher fare for the PRT would
generate revenue that could further support the entire transit
network. I view it as the equivalent to taxis, as opposed to limos,
except that the profits would flow right back into the transit
authority.
I don't understand what you mean by "getting little or no use out of
the expensive, depreciating, high capacity system" - if you are
referring to the metro, there will still be very high demand at the
peak times, it will only stop running during the inefficient off-peak,
which is a good thing. If you are referring to the PRT, I would assume
the PRT fare could be optimized to provide full utilization during the
rush: maybe it's $8/ride, maybe $4/ride, I don't know, but it would be
an upgrade over the metro so it should be somewhat higher than the
train fare. Maybe with the enhanced system efficiency, train fares
might even be reduced somewhat, which would effectively nullify the
argument that the PRT is some wealthy perk.
At a minimum, all I'm suggesting is that the neighborhood circulators
should be connected with links that run along the existing rail line,
with stations located near the existing rail stations. That way, the
700k that already use these rail lines can continue to use it, and PRT
would provide the off-peak service allowing the trains to shut down
earlier. The higher fares would apply only when the trains are
running, and only to long distance trips that could otherwise be taken
on the train. Local area circulation would not be subject to the
higher fare, so the neighborhood circulator function is unaffected by
the peak fare charge.
In essence, then, PRT would not only augment the trains during the
day, but also replace the trains entirely at night. And it should be
relatively inexpensive to implement the links along the rail lines --
just straight bidirectional runs with a few widely spaced stations,
and for that you save many hours of empty off-peak trains.
Mike C.
Brad Templeton
> But to imply that PRT can actually handle those kinds of loads today,
> that just makes us look unrealistic. When we speak about PRT vs rail,
> we need to stress the large capacity gap between light rail and
> metros, and that we're referring to the former not the latter.
>
subways, carry
just a small fraction of the population other than in Manhattan, and
that they do
it at an energy efficiency similar to passenger cars.
Small ultralight vehicles are more energy efficient than cars or
transit, but it's
true that PRT or single roads can't compete with the packed train of
commuters at rush hour. However, there is a lot more to
transportation than rush hour. And road (or PRT) networks can and do
carry far more people than a few rail lines, even packed rail lines,
if we were to use them properly.
Richard Gronning
analysis is in order.
Here's the original;
700k passengers per weekday with a record of over 1M during Obama's
inauguration. They have up to 8-car trains, with each car holding 175
crush load (70 seated, the rest standing). They run as
close to 3 minutes separation,...
Ed Anderson has planned his system for the last 20 years or more at 1/2
sec headway. About 7K/Hr
He says that a grid should be considered with guideways running at 1/2
miles apart.
The twin cities have the densest part of the population about 18 miles,
E-W and 15 miles, N-S.
Now, I'm not sure how many vehicles would be practical.
Let's say that the system can be close to maxed out.(for the purposes of
argument.)
If;
Only one person per vehicle, then 7K passengers per hour, then 168K for
24 hours How about 3, everybody seated? (You're going to
evacuate the metropolitan area)
@ 1/2 mi = 37 guideways N-S = 259K PPH, 6.2M
for 24 hours 777K PPH
= 31 guideways E-W = 217K PPH
5.2M for 24 hours 651K PPH
TOTAL = 476K
PPH 11.4M for 24 hours 1.4M PPH
The Twin Cities Metro Area is about 3.1M. With nobody standing or seated
on the floor,(which would happen during an evacuation) and just using
PRT, (which wouldn't be the case) the area could be evacuated in 2 1/4
hr. Using PRT plus all other arteries, maybe 1/2 to 3/4 hour.
The point is that PRT is a circulator operation.
People will ride it because it is convenient.
A complete circulator operation for a metropolitan area could surpass
the D.C. Metro and even commuter rail because of the number of tracks.
Dick
Richard Gronning
see how this comes out...
Richard Gronning wrote:
> Ed Anderson has planned his system for the last 20 years or more at 1/2
> sec headway. About 7K/Hr
> He says that a grid should be considered with guideways running at 1/2
> miles apart.
> The twin cities have the densest part of the population about 18 miles,
> E-W and 15 miles, N-S.
> Now, I'm not sure how many vehicles would be practical.
> Let's say that the system can be close to maxed out.(for the purposes of
> argument.)
>
If;
Only one person per vehicle, then 7K passengers per hour, then 168K for
24 hours
@ 1/2 mi = 37 guideways N-S = 259K PPH, 6.2M for 24 hours
@ 1/2 mi = 31 guideways E-W = 217K PPH , 5.2M for 24 hours
Total = 476K PPH, 11.4M for 24 hours
How about 3, everybody seated? (You're going to evacuate the
metropolitan area)
TOPAL = 1.4M PPH
Jerry Schneider
Is it profitable during peak periods? I don't know. But a substantial
majority of
daily travel occurs during off-peak periods. Deep into the night,
there are not so
many trips it would be helpful to serve the drunks.
I'm not sure that the economics of cutting back on off-peak and
wee hour schedules for those who can or need to make use of mass
transit routes would
be acceptable and particularly if the PRT vehicles were quite slow compared to
the mass transit vehicles. But, it's an interesting question and
would generate some
labor problems with the transit unions I would think.
>Charging higher fares for peak PRT would just be a way of managing the
>demand during busy times. And the higher fare for the PRT would
>generate revenue that could further support the entire transit
>network. I view it as the equivalent to taxis, as opposed to limos,
>except that the profits would flow right back into the transit
>authority.
Would the taxi drivers appreciate the competition? Again, it would be
worth looking
at how much revenue would be gained, if any, and what the reductions
in taxi business and mass transit revenue would be.
>I don't understand what you mean by "getting little or no use out of
>the expensive, depreciating, high capacity system" - if you are
>referring to the metro, there will still be very high demand at the
>peak times, it will only stop running during the inefficient off-peak,
>which is a good thing.
Maybe more good than bad - it would take some detailed analysis to
figure it out. One would have to include the negative effects of schedule
cut-backs (or termination of service) during off-peak hours and determine
who would be adversely affected by the partial or total loss of service.
Some transit riders don't have "typical" jobs and "typical hours" but still
need to get around without an auto.
>If you are referring to the PRT, I would assume
>the PRT fare could be optimized to provide full utilization during the
>rush: maybe it's $8/ride, maybe $4/ride, I don't know, but it would be
>an upgrade over the metro so it should be somewhat higher than the
>train fare. Maybe with the enhanced system efficiency, train fares
>might even be reduced somewhat, which would effectively nullify the
>argument that the PRT is some wealthy perk.
That would be important to calculate and assess the likely impacts on
the competitive systems.
>At a minimum, all I'm suggesting is that the neighborhood circulators
>should be connected with links that run along the existing rail line,
>with stations located near the existing rail stations. That way, the
>700k that already use these rail lines can continue to use it, and PRT
>would provide the off-peak service allowing the trains to shut down
>earlier. The higher fares would apply only when the trains are
>running, and only to long distance trips that could otherwise be taken
>on the train. Local area circulation would not be subject to the
>higher fare, so the neighborhood circulator function is unaffected by
>the peak fare charge.
I can remember see very large numbers of buses parked at the bus base
during off-peak periods
in Seattle so I suppose one could also park lots of train-sets. In
some cities, the buses carry
many more people than the high capacity rail systems which are often
radial to the historic downtown
area and provide much less good access non-downtown locations.
Less wear and tear except for sun damage, unless covered. Lots more
part-time transit workers
and fewer taxi drivers.
>In essence, then, PRT would not only augment the trains during the
>day, but also replace the trains entirely at night. And it should be
>relatively inexpensive to implement the links along the rail lines --
>just straight bidirectional runs with a few widely spaced stations,
>and for that you save many hours of empty off-peak trains.
Probably not empty trains but I've not got the numbers at hand.
It seems to me that given the high sunk cost of the high capacity rail
systems, one should do what they can to maximize their use and
revenue streams. The conventional concept is to deploy PRT feeder
systems to help boost their patronage. Many of the existing systems
owe lots of money to bondholders and if you cut their revenue streams
and the PRT doesn't generate the needed replacement $, there might
be some problems making payments to the bondholders.
Anyhow, it's an interesting concept and it would be nice to see it analyzed
for one or more of the several cities where it might make sense.
Mike C
All DC metro lines pass through a 0.4 sq mile area in the city center.
From what I can tell, this area is covered by 3 bidirectional track
sections which can carry 6 8-car trains into or out of the city every
2-3 minutes (maximum). That translates to 6*8*175*30 = 252,000
passengers per hour into a 0.4 sq mi area (1mi by 0.4mi). For PRT,
even at 10,000 vehicles per hour and 3 passengers per vehicle, 9
bidirectional PRT lines would be necessary in an area approximately 10
blocks long, to match the maximum capacity of the metro.
My point in this thread is that PRT will not soon replace metros in
cities like DC and NYC, maybe not ever, because the trains deposit an
enormous amount of people in a very small space. The amount of
guideway and stations required in such a small space would be
prohibitive, especially with the current public resistance to elevated
guideways - imagine telling the people of Washington DC that they were
getting an elevated bidirectional guideway over every single street
downtown.
Maybe in 20 years, when PRT is familiar and people get over their
elevation paranoia, and when regulators are familiar enough with the
technology to drop unneeded constraints like the brick wall stop, we
can talk about replacing the metros (or not -- I think a metro/PRT
combination just might be the best solution even in the long term).
But talking about it today it just makes us sound nuts.
Mike C
eph
If 4 PRT tracks fit per single direction train ROW, and tandem cars
operate in GRT mode (direct to downtown destination) at peak hours, so
8 people per tandem vehicle can be moved along at least 12 tracks,
perhaps more if empty cars are allowed to platoon meaning an
asymmetrical flow of full/empty vehicles are and we further optimize
for speed (perhaps slower than normal)...
13,000 per prt track (0.31g emergency brake, 0.15 delay, 3m cabins, 22
km/h at the confluence point) * 12 tracks = 156,000 pphpd, more with
asymmetry. Stations would be problematic.
No, it isn't pretty, but neither is a crush loaded metro.
Plan B:
BeamCars, BeamBus. BeamTaxi, BeamTrain, BeamCargo....
AKA automated electric highway.
Urbanaut is the closest I've seen yet with potential.
F.
Mike C
On Jun 28, 7:30 pm, Jerry Schneider <j...@peak.org> wrote:
> >deep into the night. This would make the metro more efficient as it
> >only needs to operate when it is most efficient and profitable, during
> >the peak times.
>
> Is it profitable during peak periods? I don't know. But a substantial
> majority of
> daily travel occurs during off-peak periods. Deep into the night,
> there are not so
> many trips it would be helpful to serve the drunks.
it is that trains are "less costly" during the peak, perhaps even to
the point of profiting operationally during the highest throughput
times.
During non-peak daylight hours, there may be times when PRT alone is
sufficient; there may be other non-peak times when the train has to
augment, but at lower service frequency. If there is a ballgame at
night, the trains can run later that night on the lines which pass the
stadium. The point is that the PRT would relieve the metro of the
*burden* of running high frequency service during low demand times.
In fact, I wonder if schedules themselves could be relaxed during the
non-peak. Perhaps trains could go into something like an on-demand
mode during those times, running only when an unexpected surge causes
an off-peak backlog.
> I'm not sure that the economics of cutting back on off-peak and
> wee hour schedules for those who can or need to make use of mass
> transit routes would
> be acceptable and particularly if the PRT vehicles were quite slow compared to
> the mass transit vehicles. But, it's an interesting question and
> would generate some
> labor problems with the transit unions I would think.
15-35mph average speed range when stops are considered.
The labor issue is always there, but there would be plenty of lead
time to plan for the reduced labor as the system is built and
integrated into the network. For example, one line at a time can be
implemented with parallel PRT, reducing the schedules on only one line
every few years.
>
> Would the taxi drivers appreciate the competition? Again, it would be
> worth looking
> at how much revenue would be gained, if any, and what the reductions
> in taxi business and mass transit revenue would be.
>
long as the system is built out, so the taxi demand would drop
gradually.
Mass transit revenue wouldn't drop unless people stop using the trains
because they don't like the PRT. But I suspect the reverse will be
true: people will ride the trains more because the PRT makes the
overall system better.
>
> Maybe more good than bad - it would take some detailed analysis to
> figure it out. One would have to include the negative effects of schedule
> cut-backs (or termination of service) during off-peak hours and determine
> who would be adversely affected by the partial or total loss of service.
> Some transit riders don't have "typical" jobs and "typical hours" but still
> need to get around without an auto.
coverage would reduce schedules, so passengers would always have
access to transit along those lines - trains or PRT during the day,
PRT at night.
>
> >and for that you save many hours of empty off-peak trains.
>
> Probably not empty trains but I've not got the numbers at hand.
> It seems to me that given the high sunk cost of the high capacity rail
> systems, one should do what they can to maximize their use and
> revenue streams. The conventional concept is to deploy PRT feeder
> systems to help boost their patronage.
metro train) the train is probably inefficient compared to PRT.
Maximizing use and maximizing revenue streams are two different
things. With trains, they are often in opposition, because revenue
drops significantly during the off-peak while costs remain the same.
> Many of the existing systems
> owe lots of money to bondholders and if you cut their revenue streams
> and the PRT doesn't generate the needed replacement $, there might
> be some problems making payments to the bondholders.
>
service. At low demand times the cost of running the trains far
exceeds the farebox revenue, so cutting those times actually improves
the bottom line. The trains would still be required -- they move tens
of thousands of people very efficiently during the rush -- they'd just
defer the lowest demand periods to a system that can operate more
efficiently in that lower demand.
> Anyhow, it's an interesting concept and it would be nice to see it analyzed
> for one or more of the several cities where it might make sense.
pursue it.
Mike C.
Jack Slade
Mike, you have something of the right idea, but it is a little off the mark.
When you say all 3 of these train systems deliver to a small area, 0.4 sq mile, do you mean they all go to the same station?
I can't believe that many people work at the station, so what area covers their real destination....the areas they walk to, after they get off the train.
It has to be much larger, because I don't think any Cities have a pop/density of over a half-million per sq mile.
Draw a grid with grid-lines 1/4 mile apart, and let me know how many intersections there are that would serve a 1 sq/mi area with a shorter walk. ( 2-level station at each int.)
I think there should be 25. Then, surrounding that sq.,mi, there should be 28 more only 1/4 mile away from the boundary.
Serving the sq/mi there are 10 lines, with 4 more only 1/4 mile away.
So you have an area of 1 sq. mile served by 106 loading platforms, no area within the square is more than 1/4 mile walk, half are a 650 ft, walk,
and if each platform can handle 40 people per minuite (like 1 small busload a minuite) then that is 1/4 million passengers per hour. That is 8 vehicles per minuite with my system, and13 VPM@ 3 Passengers per vehicle.
Now lets see of each main line can carry that # of vehicles, per minuite.
Even at 1 per/sec, each line can move 60 per/min. If 8 vehicles of that line of 60 is going to stop at one of those stations, and there are 7 stations along that area, on that line, then 56 of those cars will be able to deliver within that area.
5 passenger cars can do this OK, but 3/passenger cars would need a little closer spacing, like 0.75 second spacing. Note that Ed Andersons 1/2 mile spacing is a good place to start, but the 1/4 mile spacing nay be necessaary later on, in cities that have a huge density.
Also, I would not be surprised if a lot of those train travellers walk a whole mile to get to their real destination, and some even transfer to busses to go farther away, so the real coverage area would be 3 or 4 square miles, for that number of people.
Jack Slade
P.S. Try to understand that I am not suggesting that I, or anybody, is proposing to do this right away, with the first line. This is what it would be like after 10 yrs or more of expansion.....JS |
Robbert Lohmann
- should it?
- if yes, why?
- if metro's are doing this job already, and attracting this much
passengers, why should they be replaced?
- do you believe PRT should replace all forms of transportation?
I believe my opinion on the subject is probably known: to each system
his own. Match the characteristics of demand with the characteristics
of the system. The metro in DC and NY, although they might be special
cases, serve their purpose. I rather focus my efforts on feeder
systems to these stations to further enhance the transit network
(evolution rather than revolution).
Robbert
eph
Why? Because selecting rail likely means installing rail for most of
the system. An approach that combines the best features of rail and
PRT in a PRT compatible system would satisfy the needs of most cities
without PRT specific urban design.
I don't believe PRT should/could replace all forms of transportation
everywhere, but I do see a substantial niche for PRT between
automobile travel and public transit (basically a cheap taxi service).
F.
Richard Gronning
I seem to have the rare ability to get my ideas scrambled lately. Sorry!
I never said that I wanted to replace the D.C. Metro, but I thought that
Jerry Schneider's comments on the capacity of it was a chance to do a
hypothetical comparison. I really think that everybody on this [t-i]
site should consider the potential ability of PRT to grow into a very
high capacity system in just about any area.
You are right to make a correction that PRT won't soon replace the D.C.
Metro,(nor should it, right now) or any other system in existence. Why
should it? Such a move would certainly be disastrous for a number of
reasons.
Dick
gu...@systematica.net
Then someday some species may go extinct.
One day i will send to Jerry schneider my presentation.
Luca
Le mail ti raggiungono ovunque con BlackBerry® from Vodafone!
-----Original Message-----
Date: Mon, 29 Jun 2009 06:44:21
To: transport-innovators<transport-...@googlegroups.com>
Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
Anupam Vibhuti
Anupam Vibhuti [+91 9810070013]M
Architect & Urban Transport Planner @ Worxpace CPL [www.worxpace.net]
D 113 East of Kailash New Delhi 110065 India Tel: +91 11 41624401,2,3 Fax: +91 11 41620040 Alt MailID: vib...@worxpace.net
eph
This is an ongoing discussion about the Brick-Wall-Stops requirements
vs. proving short headways are safe and getting regulators (and the
public) to approve such systems.
Every time I drive on the highway, there are moments when even the
required 2 second headways are not maintained, usually when traffic
merges, which is possibly the most dangerous moment to have reduced
buffer space. So the concept isn't really foreign.
Much of AHS (automated highway systems) banks on platoons to increase
highway capacity, but joining and leaving a platoon at speed means BWS
are not respected at all times.
Having short headways solves all sorts of problems for PRT from
guideway cost to system capacity. Selling it isn't so easy,
especially in a rail lobby world. Some see short headways as a growth
path after a system proves to be safe - headways can be reduced to
increase capacity in the future.
F.
On Jun 29, 11:06 am, Anupam Vibhuti <anupam.vibh...@gmail.com> wrote:
> Hi,On a plain arithmetic level, PRT capacity can easily reach the metro
> multiple lines can be built within the same width of a metro)....adding up
> to the required capacity - especially PRT line which can be configured side
> ways or even one above another
>
> configurations of speed, occupancies & frequency - theoritically.
> and extending the logic further different such configurations can actually
> However what is of importance is that we need to consider the value
> advantages of 'no' transfers and 'no feeders' with a PRT system.
> With a PRT system we do not 'need' to feed into the line anyways, changing
> the rules of 'mass' transit fundamentally...!
>
Richard Gronning
Robbert Lohmann wrote:
> Can PRT ever approach the capacity of a high end metro system?
>
> return questions:
> - should it?
>
Why shouldn't it? Are we talking, "systems" or "track segment" capacity?
> - if yes, why?
>
In a metropolitan setting, a PRT system should rival (not necessarily
replace) the automobile. Same for other modes of transportation.
> - if metro's are doing this job already, and attracting this much
> passengers, why should they be replaced?
>
Economics! If it would be cheaper to run a PRT system and the PRT system
would do a better job, why not?
Here's a fantasy that I had while riding the underground in New York;
Each track could be replaced by 2 PRT guideways horizontally and 2
vertically for a series of 4 guideways for every track now existing. E-W
routing could be accomplished with small tunnels a fraction of the size
and expense of the present tubes. The convenience and therefore the
loads would go up. Buses would, or should, disappear from Manhattan.
Street traffic would be drastically reduced with a system that convenient.
> - do you believe PRT should replace all forms of transportation?
>
Since the 1st system has yet to be used by the general public, it's too
soon to answer (not necessarily to ask) that question. I'd never even
think about replacing pedestrian travel or bicycles. PRT would augment
these forms of locomotion. Why shouldn't PRT be seen (possibly for only
the time being) as an augmentation for the other forms of transportation?
> I believe my opinion on the subject is probably known: to each system
> his own. Match the characteristics of demand with the characteristics
> of the system. The metro in DC and NY, although they might be special
> cases, serve their purpose. I rather focus my efforts on feeder
> systems to these stations to further enhance the transit network
> (evolution rather than revolution).
>
And I believe that you've hit on the most important point; FOCUS! How is
a PRT system to be started, let alone developed? "Feeder ops" is the
focus!!! One job at a time. The rest, like my "tubes" thing above, is
fantasy. But, You wouldn't want to take dreams away from any one of us,
would you? Nothing will be accomplished without dreams.
Dick
Walter Brewer
PRT should be going for the growth market. What happens to other modes in
typical cities will be determined by its appeal and utility. Dense Eastern
cities like NYC, D C , Chicago are anomolies and not growing much, if any,
compared to the rest of the country. So their special use of suways, heavy
rail should not be priority.
Example San Diego's transportation plan has over $ 17 billion allocated for
mass transit by 2030. ~ 2/3 is capital funds. That's where the PRT
competition should be because it will better match demand and really relieve
congestion. Even the plan very optimistically shows mass transit share only
~5% of travel.
Of course the hope is these funds will appear somehow. But I think we will
survive the current transient and move on with healthy growth.
No one planned it, but lot's miles of rail tracks were ripped up in the
'30's to '50's once the auto's utility was estalished. Current mass transit
can also be replaced as new capability is demonstrated. Ditto for some auto
use. Just give the new animal the right feed, and go with the results.
They there were all those piston engine airplanes we bought and scrapped!
Progress progresses.
Walt Brewer
----- Original Message -----
Walter Brewer
way to demonstrate, but likely unintended consequences of perpetuating the
inferior collective system being fed.
Walt Brewer
----- Original Message -----
From: "Richard Gronning" <rgro...@gofast.am>
To: <transport-...@googlegroups.com>
gary13
> Why shouldn't PRT be seen (possibly for only the time being) as an augmentation for the other forms of transportation?
requires transfers to get to your destination. The less transfers,
the better. None is best. I suspect transfers are a significant
reason for people not using public transportation (certainly for me).
gary s
Richard Gronning
Again, the proposition is, "FOCUS!" Of course you're right and everybody
on this [t-i] list knows it. The focus is to see it up and running. I'll
buy into just about anything, (possibly for only the time being) just to
see a system built.
The lack of transfers is only one of the many conveniences of PRT.
Richard Gronning
I have great faith in the economics of PRT. Once it's built, the
economics will dictate what happens next. If the 1st system is built on
a fair grounds as an amusement ride and it's built, I'll be happy.
I really don't want to run anybody down, but over a 15 year period I've
seen, and I keep seeing wonderful intelligent people saying where PRT
should go, or not go, what it should do, how it should act. The real
proposition is, "How do we start the 1st system built in the U.S.?"
Dick
Walter Brewer wrote:
> OK. But feeder function should be way on the outer fringe of the focus. A
> way to demonstrate, but likely unintended consequences of perpetuating the
> inferior collective system being fed.
>
>
>>>
Jerry Schneider
>Walt;
>
>I have great faith in the economics of PRT. Once it's built, the
>economics will dictate what happens next. If the 1st system is built on
>a fair grounds as an amusement ride and it's built, I'll be happy.
>
>I really don't want to run anybody down, but over a 15 year period I've
>seen, and I keep seeing wonderful intelligent people saying where PRT
>should go, or not go, what it should do, how it should act. The real
>proposition is, "How do we start the 1st system built in the U.S.?"
Step 1 is an assessment and selection of the "best" available systems
Step 2 is the test track, test program and evaluation of results
Step 3 is the demo (2 -year minimum) in a public setting (e.g. Rosemont)
Step 4 is the selecting and building the an initial small-scale
network and opening it up to the public
Step 5 is the assessment of the initial deployment
Some acceleration might be possible by transporting key "money" and
"decider" people to the U.K., Sweden and/or Masdar.
Dennis Manning
Common error.
----- Original Message -----
From: "Mike C" <mwil...@gmail.com>
To: "transport-innovators" <transport-...@googlegroups.com>
Subject: [t-i] Can PRT ever approach the capacity of a high end metro
system?
>
Michael Weidler
| Dick - I think you missed something. That 7k/hr is PER GUIDEWAY. If I have more than one guideway going in essentially the same direction (such as what we experience with the road system), then I have 7k/hr TIMES the number of guideways. --- On Sun, 6/28/09, Richard Gronning <rgro...@gofast.am> wrote: |
|
To: transport-...@googlegroups.com |
|
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|
Jerry Schneider
>Mike you're doing a comparison with metro corridor versus a PRT network.
>Common error.
Yes, but -- how do you do a network capacity calculation without
using a full-fledged simulation model using
a forecast of future travel demand and including all or some of the
existing, competing modes?
Michael Weidler
| All trains pass through that small area, but not everyone or even close to everyone gets off there. From personal experience living in that area, Metro starts to shed passengers as soon as it crosses the DC border (there are some exceptions). A LOT of the reason so many people go through that small area is because they need to transfer to another line. They are not going to the surface. In other words, they can't get there from here without going through there. When I worked for NASD out near Rockville, I would take a bus from our apt to the Fort Totten Station and then take the Red Line all way DT and back out to Shady Grove, where I caught another bus for the last couple of miles of my commute. Granted, my commute was a bit on the extreme, but not all that unusual. DC has a number of draws. Medical Center in Bethesda & Catholic University (both on the Red Line but on opposite sides of DT.). Foggy Bottom on the Blue/Orange Line. The Pentagon on the Blue line in VA. Crystal City (Patent Office) also in VA. National Airport also in VA. And generally the only way to get there if you are coming by metro is to go through that .4 sq mile area. A well designed PRT system wouldn't do something that stupid. |
--- On Sun, 6/28/09, Mike C <mwil...@gmail.com> wrote: |
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Michael Weidler
| You have an interesting notion about how GRT works. Wrong, but interesting. GRT only works in PRT mode during off-peak. During peak it runs sort of like an express elevator. It by-passes stops not selected by the current riders. However, it may well stop at every station depending on where the various riders want to get off and whether any new riders with DIFFERENT destinations get on at any of those stops. --- On Sun, 6/28/09, eph <rhaps...@yahoo.com> wrote: |
|
Date: Sunday, June 28, 2009, 9:28 PM |
|
Dennis Manning
network will perform (i.e. how many will it transport from desired O to D in
a given time) is not a function of the capacity of a single segment of the
system. I don't think the line haul capacity of a mass transit system
necessarily tells the overall performance either, it's likely to be a better
predictor in a corridor than a network.
I'm not stating anything that you or most on the ti-list don't already know,
but in going from one station to another in a corridor there is only one
path. In a network there are many paths. The complicator in all this is of
course that the Os and Ds shift when comparing any particular time period.
Modeling the shift would be much more difficult in a network than in a
corridor.
----- Original Message -----
From: "Jerry Schneider" <j...@peak.org>
To: <transport-...@googlegroups.com>
Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
system?
>
Michael Weidler
| DC does m-f 8a-6p. I'm not exactly certain where Mike C is measuring, but the rectangle bounded by the various Metro Lines contains most of the federal office buildings, the Capitol, the Supreme Court, the Library of Congress, the National Archives and scads of non-gov office workers. This is not to contradict my earlier post to Mike C about transfer patterns in that area. A substantial portion of riders are simply transferring to a different line to get where they really need to go. --- On Mon, 6/29/09, Jack Slade <skytr...@rogers.com> wrote: |
|
To: transport-...@googlegroups.com |
|
|
|
eph
destination and drop them off there. Whatever it's called, that's how
it could work.
F.
On Jun 29, 8:41 pm, Michael Weidler <pstran...@yahoo.com> wrote:
> You have an interesting notion about how GRT works. Wrong, but interesting. GRT only works in PRT mode during off-peak. During peak it runs sort of like an express elevator. It by-passes stops not selected by the current riders. However, it may well stop at every station depending on where the various riders want to get off and whether any new riders with DIFFERENT destinations get on at any of those stops.
>
Mike C
Yes, that's true about the center being a transfer point. But there
are some times (i.e. inaugurations) when literally everyone is going
to the center.
But the real point I was trying to make is that influential people in
places like DC and NYC have a perception of "rail" which is
significantly different than the reality in most cities. They see rail
at its most effective and efficient, moving huge masses of people in a
short amount of time, so the notion that PRT can be a serious transit
system like metros is ludicrous. 10000 passengers/hr doesn't faze
them.
What they don't realize is that most rail lines in cities (in the US
anyways) are MUCH less capable and effective than their metros. It is
THOSE systems which PRT aims to replace, not the metros, but that fact
gets muddied. And the advocates of these light capacity rail systems
like to keep it that way. Why do they think they changed the name from
"streetcar" to "lightrail" -- they are essentially riding the
reputation of the high end systems that move 5 times what they can
move. So I think it's important to keep pounding the point that all
rail systems are not created equal, and PRT only aims to replace the
lighter capacity versions.
Later on we can take on the tubes, IF it makes sense. Maybe we'll find
that a metro/PRT blend is the best of both worlds.
Mike C
On Jun 29, 8:15 pm, Michael Weidler <pstran...@yahoo.com> wrote:
> All trains pass through that small area, but not everyone or even close to everyone gets off there. From personal experience living in that area, Metro starts to shed passengers as soon as it crosses the DC border (there are some exceptions). A LOT of the reason so many people go through that small area is because they need to transfer to another line. They are not going to the surface. In other words, they can't get there from here without going through there.
>
> When I worked for NASD out near Rockville, I would take a bus from our apt to the Fort Totten Station and then take the Red Line all way DT and back out to Shady Grove, where I caught another bus for the last couple of miles of my commute. Granted, my commute was a bit on the extreme, but not all that unusual.
>
> DC has a number of draws. Medical Center in Bethesda & Catholic University (both on the Red Line but on opposite sides of DT.). Foggy Bottom on the Blue/Orange Line. The Pentagon on the Blue line in VA. Crystal City (Patent Office) also in VA. National Airport also in VA. And generally the only way to get there if you are coming by metro is to go through that .4 sq mile area. A well designed PRT system wouldn't do something that stupid.
>
Dennis Manning
I try and stay out of PRT/GRT debates as it's already been thrashed quite a
bit, but for GRT supporters I have a question: On the freeway system
virtually any size vehicle can ride. Why are there so few GRT size vehicles?
However, while Morgantown can operate in PRT mode it never does. In the off
peak hours they tried the the PRT mode, but after analysis decided that the
non-PRT mode was less expensive to operate.
Jack Slade
The second question is not a riddle. If you make a vehicle big enough for GRT, then it is not efficient as PRT, plus you need more vehicles.
The first is also obvious. The only GRT I see on arterials connecting my city to Toronto are express busses, once per hour, that will take you to 2 destinations in Toronto. If lots of people used them, they would still be miles from their real destination, making it a 2 hr trip, instead of the 45 min. it takes by the family car.
People who move to the suburbs go there because they plan it all around the car. Then gas price quadruples, in the same year that higher mortgage rates kick in, a bunch of them can't afford both increases, and you get the current mess everybody is in. Why the surprise?
Question: If we already had PRT started 10 years ago, to give them a way to avoid one of the increases, would the recession still have happened?
|
Charl du Toit
________________
- Charl
www.camdek.com
Dennis Manning
Dennis Manning
day and special events taking place, but yes. It's more about demand at the
stations than capacity of the links.
Robbert Lohmann
I am not about to steal anybody's dream ;-) More specifically I am
interested in what steps should be taken to realize the dream. And I
actually get to realize several of them at the same time (introducing
innovation, changing the world a little bit and setting up and being
succesfull with 2getthere) - which is why I feel I am blessed.
And although it's good to dream (big), sometimes dreams should not be
shared with the public!
The main reason being that dreams are sometimes unrealistic and
actually cause people to avoid the matter they regard because of the
high fantasy level; so if you do dream, and you communicate about your
dreams, make sure you make very explicit it is a dream...
Robbert
eph
agree is not very popular. I think taking the driver and organization
work out of this mode would make it more palatable, plus in the
scenario below, there would be no alternative for public transit into
the city core. Issues with this idea include larger stations needed
to queue people up (or simply wait) by destination, similar to a bus
stop.
I prefer plan B, the train plus PRT and any other type of vehicle the
guideway could handle because it's utilization of resources (the
guideways) is better. One of the failings of rail, as I see it, is
lack of flexibility/utility compared to a road.
F.
On Jun 30, 1:50 am, "Dennis Manning" <john.manni...@comcast.net>
wrote:
Walter Brewer
Walt Brewer
From: "gary13" <garyd...@gmail.com>
To: "transport-innovators" <transport-...@googlegroups.com>
Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
system?
>
Walter Brewer
Jerry Schneider
>GRT (or my new? version of it) is equivalent to car pooling which I
>agree is not very popular.
I agree that that is the common perception. However, I've noted that the
2006 daily vehicle trips in the Puget Sound region were 8+ million
while the person trips were 13+ million. Sounds like considerable
car-pooling (or something) is going on - with lots of potential for more
if the situation warrants it.
- Jerry Schneider -
Innovative Transportation Technologies
http://faculty.washington.edu/jbs/itrans
Jerry Schneider
>Stop looking at links, and define nodal inputs...that's apples and apples.
some future time?
Can you elaborate?
Dennis M wrote --
> > I'm not stating anything that you or most on the ti-list don't already
> > know, but in going from one station to another in a corridor
> there is only one
> > path. In a network there are many paths. The complicator in all this is of
> > course that the Os and Ds shift when comparing any particular time period.
> > Modeling the shift would be much more difficult in a network than in a
> > corridor.
(pm is usually
greater). You would need demand forecasts for mid-day, evening and wee hours to
analyze the off-peak situations - so far as I know, such forecasts
are beyond the capabilities
of current forecasting models. And, the sum of the am and pm peak
periods is only
around 30-40% of the total daily person trips in a metro area. Trying
to extrapolate the
peak-period data to the off-peak periods would be quite difficult as
the types of trips
during the two periods are likely to be substantially different.
> >
> >
> > ----- Original Message -----
> > From: "Jerry Schneider" <j...@peak.org>
> > To: <transport-...@googlegroups.com>
> > Sent: Monday, June 29, 2009 4:46 PM
> > Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
> > system?
> >
> >
> >>
> >> At 03:34 PM 6/29/2009, you wrote:
> >>
> >>>Mike you're doing a comparison with metro corridor versus a PRT network.
> >>>Common error.
> >>
> >> Yes, but -- how do you do a network capacity calculation without
> >> using a full-fledged simulation model using
> >> a forecast of future travel demand and including all or some of the
> >> existing, competing modes?
> >>
> >>
> >>
> >>
> >> >
> >
> >
> > >
>
>
>
Kirston Henderson
> At 06:06 AM 6/30/2009, you wrote:
>
>> GRT (or my new? version of it) is equivalent to car pooling which I
>> agree is not very popular.
>
> I agree that that is the common perception. However, I've noted that the
> 2006 daily vehicle trips in the Puget Sound region were 8+ million
> while the person trips were 13+ million. Sounds like considerable
> car-pooling (or something) is going on - with lots of potential for more
> if the situation warrants it.
We must also remember that cars often carry families and that means that
there will always be more person trips than vehicle trips.
Kirston Henderson
MegaRail®
eph
per vehicle trips. This number certainly seems higher than the usual
average for commuters (1.1?).
F.
Jerry Schneider
>With a 1.6 average it's difficult to know how many are 3 or 4 person
>per vehicle trips. This number certainly seems higher than the usual
>average for commuters (1.1?).
If by commuters, you are referring to journey-to-work trips, then remember
that the Puget Sound number are daily trips, only a portion of them are j-t-w
(commuter) trips. Off-peak trips are in the majority and they tend to have
greater occupancy levels that j-t-w trips. The figures show 13+ million daily
person-trips and a little less that 2 million jobs in the region.
This suggests that
something like 11 million person trips are not "commuter" trips.
Walter Brewer
least 3 to 1.
P S at 1.6 sounds like the national average quoted by USDOT. Number used in
San Diego is about 1.35, and I don't know why the difference. Commuter
occupancy is about 1.15
Walt Brewer
From: "Kirston Henderson" <kirston....@megarail.com>
To: <transport-...@googlegroups.com>
Jerry Schneider
>I assume these trips by autos only? The ratio for typical mass transit is at
>least 3 to 1.
The term used is "vehicles" - ask them if you want a definition, I
don't have it.
>P S at 1.6 sounds like the national average quoted by USDOT. Number used in
>San Diego is about 1.35, and I don't know why the difference. Commuter
>occupancy is about 1.15
Might be based on observed data or made-up (or emulated) data. Ask for sources,
if you wish. San Diego is certainly a different place than Seattle.
Physically and culturally.
I don't know how different but there is no reason I know of to expect
them to have the
same daily travel attributes.
Michael Weidler
| And not surprisingly these non peak trips are pretty much congestion free until they get to an activity center. --- On Tue, 6/30/09, Jerry Schneider <j...@peak.org> wrote: |
|
Richard Gronning
One more time;
One short line at a time.
1 Passenger /cab = 7K passengers / Hr = 168K /24Hrs
Stations @ 1/2 mi.
37 tracks, N-S = 259K pph, = 6.2M 24Hr
31 tracks E-W = 217K pph, = 5.2M 24 Hr
Total = 476K pph, = 11.4M 24 Hr
3 passengers per cab, evacuation of city
Total = 1.4M pph
This was only a silly exercise to point out that PRT could have a large
capacity. As has been pointed out, the real world doesn't work like that
and the actual calculations for a system would be very complicated.
More to the point, people WILL want to ride PRT because of ease and
convenience. And PRT can transport LARGE numbers of HAPPY people.
Let's see how badly this one gets scrambled.
Dick
Richard Gronning
Thank you for this personal note. Of those among this group, you truly
are blessed!
While my dream of replacing the tracks in the N.Y. tubes with PRT
guideways is pure fantasy, it does have some amount of merit to it.
There really is room for 4 PRT guideways for every track in the N.Y.
tubes. If it were economical, why not? Cross-tracks in considerably
smaller tubes are certainly a possibility. And such a system could move
considerably more people in considerably more comfort.
Another reason to consider such a system is the potential in Europe.
Europe , as you know more fully that we Americans, has beautiful
Medieval and Renaissance cities. As you know, Europeans really object to
overhead transit systems no matter how small. That leaves either surface
systems, or below-surface systems. There are mole-type diggers used for
cutting new aqueducts for N.Y., high pressure water diggers, and the
like that could be built smaller (and faster) to put underground
channels for PRT.
A dream?
Dick
Mike C
light rail line in Minnesota, which competed directly with PRT. It is
considered an enormous success carrying 37k passengers per weekday -
compare this to more than 100k per line on the Washington metro.
It has 2-car trains carrying up to 400 passengers (2/3rd standing),
running at 7.5 minute frequency during the rush. That's 3200
passengers/hr max capacity. They are expanding stations to allow 3-
vehicle trains, or 4800 passengers max capacity. Even at conservative
headway assumptions, the Minneapolis PRT proposal was capacity-
competitive with this rail system even in a SINGLE PRT loop. With
lower PRT headways (the system was engineered for operation down to .5
seconds), PRT would have nearly doubled the 3-car train crush capacity
per line single line.
The rail system cost something like $60M per mile for 3200 passengers
per hour capacity. Metros can carry TEN TIMES that number. And the
Minnesota system runs on streets, so they can't even increase
frequency to enhance capacity -- even at 7.5. minutes there have been
signal problems causing long delays in auto/bus traffic which crosses
the rail line. So once they expand to 3 car trains, they have no other
avenue for increasing capacity beyond the max 4800 passengers/hr on
that line.
The PRT system could have easily matched this capacity with a single
line, and costs per mile would have been comparable even using
pessimistic PRT projections. And for similar cost per capacity, the
PRT would:
- provide 24hr service. The Minneapolis LRT shuts down for 4 hours at
night and runs reduced frequency evenings and weekends.
- have shorter wait times. They'd have quivalent wait times during the
peak, but PRT would be much better in evenings.
- give every single passenger a seat and plenty of room. The LRT at
max capacity forces two thirds to stand in packed trains.
- likely operate without subsidy. The LRT is subsidized at about $1.30
per passenger, even though ridership has exceeded all expectations.
- not impact road traffic.
This LRT system is considered a resounding success, but the proposed
PRT system would have exceeded it on every single metric, even
*capacity*. Yet naive people have ridiculed PRT even as they praise
this system. It seems that Minnesotans don't really understand that
their rail system is a *TOY* compared to the big metros. They hear
"rail" and just assume that the Minneapolis LRT somehow gets them
closer to world class systems like DC and NYC. Nothing could be
further from the truth.
These are the misconceptions we need to correct if PRT is ever going
to be accepted as a viable system in this country. PRT looks like a
toy when compared to metros, but it looks quite attractive when
compared to "successful" light rail. We should be educating the public
on the difference.
Mike C.
Walter Brewer
the line, and what share of the regions total?
Walt Brewer
----- Original Message -----
Walter Brewer
subway or surface in big dense cities".
That is if the "dream" PRT is not just corridor parallel, but can follow the
existing multiple ROW's direct to destination without incurring the transfer
nightmare. In Manhattan for example the existing system is extensive enough
as an area process to meet desirable walking distance specs.
There would especially be an advantage if the initial installations could
operate in parallel with the existing they will replace.
Walt Brewer
From: "Richard Gronning" <rgro...@gofast.am>
To: <transport-...@googlegroups.com>
Sent: Wednesday, July 01, 2009 11:35 AM
Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
system?
>
Mike C
Here are some links that contain the data I referred to:
http://www.metrotransit.org/rail/
http://www.metrotransit.org/rail/facts.asp
http://www.metrotransit.org/images/HLRT_stats.pdf
In 2007, there were 9.1M passengers, 51.7M passenger miles, $7.9M in
fares, and $12.5M subsidy. According to the website, fares are
supposed to be $1.75 to $2.25 per passenger, but they only collected
less than half that, about $0.87 per passenger. Either they overstated
ridership or they don't count transfer fares from the buses. Or maybe
half the passengers are evading the fare.
I should reiterate that, by most accounts, this is a model light rail
system in both design and implementation. Yet PRT could have done
better for the same capital cost, and would not cost $12.5M/yr to run.
The problem is that the opposition screams "anti-rail! anti-transit!"
whenever we state these facts, so emphasizing our support for high end
rail will help to disarm that smear.
Mike C.
Richard Gronning
I think that if I may carry on with my fantasy, Maybe I can even suggest
some priorities. In these tubes there are both locals and express
tracks. In some areas I vaguely remember that there may be as many as 8
tracks. (Maybe I remember incorrectly) At any rate, there are 4 tracks
abreast. The express tracks could be put into PRT 1st and then the rest.
Because of the large passenger loads for this system another feature
could be added. Consider that PRT has off-line stations. This would be
the case with these tubes. There's plenty of space to put this feature
in. How about extending the concept to the existing concept of express
tracks? There are presently both local and express tracks. The
difference is that the PRT system would have multiple connecting tracks
to relieve loads. In effect, some of the guideways would become higher
speed express tracks. The express lanes lead to local lanes like the
present PRT concept of guideways lead to off-line stations.
Is this such a bad dream?
Dick
eph
tunnel/space. I've been searching for such a solution for years and
very few qualify. Some are too tall, some too wide, others are speed
challenged (for my application).
F.
eph
http://docs.google.com/View?docID=dfbfrhxh_08mbwjscw&revision=_latest
http://www.geocities.com/rhapsodiser/
F.
Walter Brewer
eph
Dennis Manning
My 2 cents: The smallest cross section PRT that I'm aware is "applied
levitation". http://www.appliedlevitation.com/ They have both PRT and GRT
designs. AL is also working with "Fastrack" group for a way to convert the
NYC subway system to a maglev system.
To get 4 PRTs in a tunnel one approach might to use suspended system on top
of a supported system. They might fit.
London may present a place to test and start. I've read that the London
subway system has something like 60 abandoned stations.
Dennis
Jerry Roane
Do you have any maps of these abandoned tunnels? It seems that if transit was a business that the sunk cost of tunneling and building a station would require that no station could be abandoned ever. In the US model rather than tunnel to where people want transit we would simply require, by building code, that TOD be built on the station. If rail is so valuable to the commerce of a community then how is it even possible that London would have any abandoned track or stations much less 60.
I would like to chime in on how many angels fit on the head of a pin. Our IP describes a minimum frontal area that is a circle. A circle gives the most area per perimeter. Our 4-passenger car is 48.475 inches in diameter (wheels retracted). If we leave a small gap we can get 4 or 6 guideways in the space of an antique subway train in London ( http://en.wikipedia.org/wiki/London_Underground_1973_Stock 2,629mm w x 2880mm h or the tall version) if my Internet found numbers are correct. Retrofitting the subways with modern advanced transportation would be easy and cheaper than maintaining what they have now. We would naturally slow down to match the tunnel trajectory but because we intend to accelerate and brake aggressively with safely seated customers we can move the flow of people of these subway trains because we better use the time the trains are not rolling on a section of rail. 6 guideways at 6923 cars per hours gives each tube a capacity of 166,153 seated passengers per hour. This number is not realistic because rail cars are not always full and neither will any system. Ridership is everything when talking real capacity. On-demand does put a minimum of 1 passenger per four moving seats though. It may be that the fit of the train car to the tunnel would allow 6 or 9 guideways per tunnel that depends on the present gap to the tunnel wall.
Jerry Roane
Dennis Manning
Charl du Toit
one-to-one link with PRT multipath links, so don't try.
But you can always ring-fence an origin and destination (each of which may
contain multiple PRT stations if needed) and compare the transport modes'
performance between them. LRT may have an extra "walk" leg is all.
There will generally be a design case (defined by time of day, or event)
which will determine node capacity requirements. Note that the constraint
generally is in the station, not in the link.
The usual transport indicators such as duration, wait, energy use etc etc
will determine the best option, which can then be costed.
It's then quite quick to generate a level of service vs cost comparision.
_________
-Charl
Dennis Manning
think making the system capacity versus line haul comparison can be useful
depending on who you are talking to.
You too easily dismiss the "extra walk leg" of LRT. It's that extra walk leg
that kills the favored TOD concept that planners are clinging to.
The fexibility of matching PRT station capacity to demand is a big
advantage.
Sure, doing almost all of this is easier with hindsight.
Dennis
Charl du Toit
The message you bear will confuse the audience, so don't go there.
You cannot "prove" a general case for network vs linehaul.
Work on the strong points such as amenity, and when you have a specific
scenario, design for the task in hand.
I am approaching this simply as a potential client would.
Dennis Manning
I wouldn't dream of putting the argument in front of a general audience.
It's all about putting the argument in front of the decision makers.
What client are you referring to? I presume it would be the local transit
agency.
Charl du Toit
untechnically minded.
I suppose it has to do with the amount of totally booney stuff they are
bombarded with.
You'd have seen how 'they" go defensive, the moment one of their
commonly-held beliefs is challenged.
There has been comment here about complementing existing technologies, and I
think that's the right place to start: humbly, and emphasizing teh
positives, rather than comparitives.
2.5c worth (inflation-adjusted)
Richard Gronning
with LRT on a line-haul operation?
OK, in Europe there must be laws about the brick-wall stop. Maybe that
is the reason.
In the U.S., they're APM standards and not laws. Even Vectus should have
a control system that can do, say, one second headway if it were allowed.
If allowed, then Vectus, with 4 passengers, could possibly do 14K pph
seated and comfortable. LRT? 4K - 6K, standing, crowded and uncomfortable.
So, the problem of comparing even a line-haul operation is the concept
of brick-wall stop?
As far as explanations, math proves that PRT can match the capacity of
LRT under any circumstances.
For people who study PRT, there is another problem with line-haul ops;
station wave-off. If a system is built only from point A to point B and
the system becomes busy, there'll be station wave-off. Therefore, a PRT
system must be built as an area circulator first. When areas are
completed, then these areas can be connected, line-haul fashion. (Thanks
for the explanation, Jeral!)
Dick
Dennis Manning
capacitiy number. LRT people come up with their maximum line haul capacity.
Dennis Manning
that we don't come off as well as comparing "system wide" capacity. If fact
line haul to line haul comparison is the way it's usually done. System
capacity for PRT is higher because when one goes from say station 22 to
station 83 there is more than one route to get there. Another way to say it
is that every trip doesn't need to use same line at any given time.
Dennis Manning
capacity, in Denver years ago when PRT was competing with LRT they made the
specs call for a capacity of 14,000 pphpd. That effectively took PRT out of
the running. I don't have the highest peak hour number for Denver's LRT, but
I'd bet it's no more than 4,000.
Richard Gronning
that buy transit are used to such an approach, it's a foot in the door.
I really like Rich Gow's approach (that you reminded us about.) After
the "usual" opening, show pictures and graphs of the area solution and
what it means.
Dick
Dennis Manning
Yes, I think graphics of the type at David Dow's web site could be used to
good advantage especially for a general audience. Emphasizing the number of
stations you get for a given a cost is easier for people to grasp. For TOD
advocates the emphasis could be the walkable area versus cost.
Dennis Manning
Charl du Toit
"Network Capacity" has this feel of a whole lot of stuff being stirred in
the round.
Line haul is easily understood by everybody - it goes from Here to There.
I never want to go anywere except from Here to There.
Demonstrate you can go from Here to There better (pick any O-D pair), and
your audience is with you, be they lay or professional.
You might also have to convince them that going There via the next city
would be to their advantage, if the network loading demands it.
_________
- Charl
Kirston Henderson
>
> I think that the idea is to start off with the familiar. Since the folks
> that buy transit are used to such an approach, it's a foot in the door.
> I really like Rich Gow's approach (that you reminded us about.) After
> the "usual" opening, show pictures and graphs of the area solution and
> what it means.
>
This approach is precisely the approach that MegaRail® has elected to
take with its MicroRail system. First sell it as an elevated mass transit
system with LRT capacity and then add local PRT loops from those main lines
in the future. Of course, I have really receive a lot of flack by several
members of this group for our company's approach attempting to sell
something other than PRT.
Frankly, I am convinced that this is the fastest way to really get to
the ultimate combination PRT/DM in service. The early mass transit trains
are likely to eventually disappear from these systems.
Kirston Henderson
MegaRail®
Dennis Manning
I can't second guess your approach as no city except the unique Masdar has
bought PRT. My sense is that the likely evolution is adoption at airports or
maybe campuses and then extending them outward. Very interesting watching
all the efforts around the globe. Especially as the number of them is rising
rapidly.
Dennis
----- Original Message -----
From: "Kirston Henderson" <kirston....@megarail.com>
To: <transport-...@googlegroups.com>
Sent: Sunday, July 05, 2009 3:06 PM
Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
system?
Richard Gronning
I am sorry. I really try to get people's names right.
Kirston Henderson
> Kirston:
>
> I can't second guess your approach as no city except the unique Masdar has
> bought PRT. My sense is that the likely evolution is adoption at airports or
> maybe campuses and then extending them outward. Very interesting watching
> all the efforts around the globe. Especially as the number of them is rising
> rapidly.
I can't guarantee success, but that is our approach and, so far, we have
managed to attract some interest. We shall have to wait and see.
Kirston Henderson
MegaRail®
eph
for mass transit" as an answer - implying that PRT could not move the
required numbers. I heard the same misinformed statement from city
staff. 14,000 pphpd can be accomplished with PRT using 4 lanes to a
rail-sized ROW and GRT rules at peak periods degrading the system to
LRT/BRT type of service at those times. Tough sell that should not
be, wondered if they just didn't want to hear it. A solid - "Yes we
Can meet LRT levels of service" should get PRT a foot in the door. It
matters for this reason alone.
F.
Sergey Prokhorenko
----- Original Message -----
From: "Jerry Schneider" <j...@peak.org>
To: <transport-...@googlegroups.com>
Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
system?
>> "How do we start the 1st system built in the U.S.?"
>
> Step 1 is an assessment and selection of the "best" available systems
Step 1 is impossible, because there are no ready good available systems on
the market. There are either raw concepts only, which need capital for R&D,
or very limited concepts with ready test tracks, the only advantage of which
is wasted money. There is nothing to select. I am sure government should
support the promising concepts from the early seed stage. There is no shop
shelf, where good ready projects wait for public procurement.
> Step 2 is the test track, test program and evaluation of results
There is nothing to test at test track.
> Step 3 is the demo (2 -year minimum) in a public setting (e.g. Rosemont)
There is no need to demonstrate anything to anybody. It's no more reasonable
than demo of space shuttle. Private investments will not go to such a risky
industry before the first profit from the first commercial network.
Sergey Prokhorenko,
SkyTaxi
> Step 4 is the selecting and building the an initial small-scale
> network and opening it up to the public
> Step 5 is the assessment of the initial deployment
>
> Some acceleration might be possible by transporting key "money" and
> "decider" people to the U.K., Sweden and/or Masdar.
Jerry Schneider
> >> "How do we start the 1st system built in the U.S.?"
> >
> > Step 1 is an assessment and selection of the "best" available systems
>
>Step 1 is impossible, because there are no ready good available systems on
>the market. There are either raw concepts only, which need capital for R&D,
>or very limited concepts with ready test tracks, the only advantage of which
>is wasted money. There is nothing to select. I am sure government should
>support the promising concepts from the early seed stage. There is no shop
>shelf, where good ready projects wait for public procurement.
There are currently three "available systems - ULTra, Vectus and 2getthere.
An assessment study could be done to pick one or two for possible governmental
support, as part of a loan or grant program. The US government has
just announced
a loan of more than $400 to Telsa Motors to further its development
and cost reductions,
as an example. Ford is also getting a large loan to help it get its
best cars to the market
faster.
> > Step 2 is the test track, test program and evaluation of results
>
>There is nothing to test at test track.
Then why is ULTra conducting tests at Heathrow Airport for
approximately 6 months before
putting their system into public service - in addition to the
extensive tests done at their test
facility. What Vectus and 2getthere are doing, is unknown to me.
Evaluation is important
to help prospective clients and investors assess the utility of such
systems before committing
to their adoption. To skip this step and than have a very visible
failure of some type, would be
very detrimental.
> > Step 3 is the demo (2 -year minimum) in a public setting (e.g. Rosemont)
>
>There is no need to demonstrate anything to anybody. It's no more reasonable
>than demo of space shuttle. Private investments will not go to such a risky
>industry before the first profit from the first commercial network.
That's not an appropriate analogy. The public consists of highly
variable humans, each of
which exhibits behaviors that can deviate from the norm in
considerable ways. Checking out
the interaction between these human behaviors and the automated
technology is just as important
as testing the hardware and software. Private investment will go to
small initial projects, if presented
with the necessary assurances and reasonably priced insurance
coverage - if they see any prospect
of profit and/or sufficient public subsidy to make it a prudent investment.
Sergey Prokhorenko
----- Original Message -----
From: "Jerry Schneider" <j...@peak.org>
To: <transport-...@googlegroups.com>
Sent: Monday, July 27, 2009 12:42 AM
Subject: [t-i] Re: Can PRT ever approach the capacity of a high end metro
system?
>
>
>> >> "How do we start the 1st system built in the U.S.?"
>> >
>> > Step 1 is an assessment and selection of the "best" available systems
>>
>>Step 1 is impossible, because there are no ready good available systems on
>>the market. There are either raw concepts only, which need capital for
>>R&D,
>>or very limited concepts with ready test tracks, the only advantage of
>>which
>>is wasted money. There is nothing to select. I am sure government should
>>support the promising concepts from the early seed stage. There is no shop
>>shelf, where good ready projects wait for public procurement.
>
> There are currently three "available systems - ULTra, Vectus and
> 2getthere.
with low capacity, without DM capabilities. It's a dead-end branch of
evolution tree. Neanderthalers became extinct. Sunk cost.
> An assessment study could be done to pick one or two for possible
> governmental
> support, as part of a loan or grant program. The US government has
> just announced
> a loan of more than $400 to Telsa Motors to further its development
> and cost reductions,
> as an example. Ford is also getting a large loan to help it get its
> best cars to the market
> faster.
>
>> > Step 2 is the test track, test program and evaluation of results
>>
>>There is nothing to test at test track.
>
> Then why is ULTra conducting tests at Heathrow Airport for
> approximately 6 months before
> putting their system into public service - in addition to the
> extensive tests done at their test
> facility. What Vectus and 2getthere are doing, is unknown to me.
> Evaluation is important
> to help prospective clients and investors assess the utility of such
> systems before committing
> to their adoption. To skip this step and than have a very visible
> failure of some type, would be
> very detrimental.
ULTra is a marginal monopolistic system for transportation of very wealthy
people, it will survive in places like Heathrow only.
>
>> > Step 3 is the demo (2 -year minimum) in a public setting (e.g.
>> > Rosemont)
>>
>>There is no need to demonstrate anything to anybody. It's no more
>>reasonable
>>than demo of space shuttle. Private investments will not go to such a
>>risky
>>industry before the first profit from the first commercial network.
>
> That's not an appropriate analogy. The public consists of highly
> variable humans, each of
> which exhibits behaviors that can deviate from the norm in
> considerable ways. Checking out
> the interaction between these human behaviors and the automated
> technology is just as important
> as testing the hardware and software. Private investment will go to
> small initial projects, if presented
> with the necessary assurances and reasonably priced insurance
> coverage - if they see any prospect
> of profit and/or sufficient public subsidy to make it a prudent
> investment.
subsidy - no investments.