From: lip@s1.gov (Loren I. Petrich)
Newsgroups: ba.transportation
Subject: Re: Cost of transit systems vs highways
Date: 31 Aug 92 19:20:19 GMT
Organization: LLNL


In article <1992Aug28.222826.25931@ntmtv> adrian@ntmtv.UUCP (Adrian Brandt) writes:
>In article <1992Aug28.175138.23709@s1.gov>, lip@s1.gov (Loren I. Petrich) writes:
@ In article <9208281421.AA05078@asia.fai.com> vaughnw@asia.fai.com (Vaughn Wolffe) writes:
@ >Bay Bridge, it carries over 250,000 vehicles a day at an average 
@ >occupancy of 1.13 per vehicle. Considerably less than half use BART.

@ 	250,000 vehicles/day??? That strikes me as a bit much.

@ 	It's a ten-lane bridge, and if one vehicle/s managed to pass
@ through each lane, then they would take 7 hours for all of them to
@ make it.

>The max sustained lane throughput I've heard thrown around a lot is 1,800
>to 2,000 cars/hr., or a car every 1.8 to 2 seconds.  A 10-lane bridge
>(5 on each deck) would have to run all 10 lanes at full bore (maximum
>throughput) for 12.5 to 13.9 hours to do this.  Since there are 24 hours
>in a day, it seems the 250,000 vehicle per day figure is *possible*.

	Possible, yes. But given the traffic jams I've experienced on
it, I wonder if the CalTrans people have overestimated how many people
cross it.

	I recall that the figure for the Golden Gate Bridge is
something about 20,000-30,000 or so cars/day, and the GG Bridge also
has traffic jams.

	Since the Bay Bridge (and the other Bay Area bridges) have
toll plazas, it should be possible to get an exact vehicle count for
the directions that tolls are collected on.

@ 	How well does CowTrain, er, CalTrain work???

@ 	It is much _less_ successful than BART in getting people out
@ of their cars.

>No less succussful than BART would be with the *same* frequencies on
>the *same* tracks.  Based on various average speed calculations I have
>done for BART lines that are similar to the CalTrain line, I'm certain
>BART's average speeds would be only a few mph better.

	If CalTrain ran at the _same_ frequencies, yes. But one
wonders what that would do to the locos if they ran for (say) 5 or 10
times as much per day. They'd break down 5 or 10 times faster unless
they get a _lot_ of preventive maintenance (for BART, the schedule is
once ever 500 (Rohr) or 600 (Alsthom) hours).

@ 	And your proposed BART clone can be had only at the expense of
@ buying _lots_ of extra rolling stock, to say nothing about upgrading
@ the stations to make them look like BART-clone stations.

>Loren, please explain in detail why "_lots_ of extra rolling stock
>would be necessary.  ...

	[On why only a certain amount of train is necessary to fill up
the route...]

	I concede the point.

	I guess "new" might be more like it, since if the line is
electrified, the 20 F40's will have to be replaced with electric
locos. And if one really wants to get fancy, one might replace all the
rolling stock with the sort of MU cars doing service in the Philly
area or New Jersey.

>For example, I calculated that to fill the roughly 50-mile SF-SJ part of
>the line with trains spaced at 15 min intervals in both directions at
>a 40 mph average speed (a train every 10 miles on each of two tracks),
>you'd only need 10 trains.  CalTrain already has 20 locos and 73 cars.
>This means you could have 10 spare locos being serviced or standing
>by, while 10 were out on the line each pulling 6 car trains.  Each
>one of these trains would have seating for about 870 people, so you
>get a people moving capacity of 3,480 people per hour per direction,
>for a total of almost 7,000 per hour.  That's roughly equivalent to a
>four lane freeway's max throughput.

	Can a CalTrain car really hold 145 people? I estimated the
seating capacity once, and it was about 78 people. By comparison, the
BART cars can seat 64 or 68 people.

	Repeating your calculations, it would be about 1900
people/hr/direction or 3800 total.

	Interestingly, BART comes pretty close on off-peak times.

	This 15-minute headway would probably be for off-peak times;
there would clearly be more demand for rolling stock on peak times,
and one would need more than the current amount for an expanded
CalTrain.

@ 	What's this grudge against BART that you seem to have?

>I won't speak for Vaughn, but I think it's s too expensive and too
>politicized for starters.  After that, I'd say it isn't compatible
>with much of anything and if it ever (god forbid) actually replaced
>CalTrain's tracks (I doubt it), you'd lose the ability to bring
>other trains like a future LA-SF TGV-style high speed rail service,
>or Amtrak passenger trains, or freights down the peninsula and into
>or near the city of SF and its airport.

	Adrian, I'll give you credit for at least one thing. You don't
have Vaughn's bile.

	I don't know if being too expensive and too politicized is a
fair criticism for a system of BART's size. If CalTrain was to be
expanded in a big way, I'm sure that it would go the way of BART in
this regard. For starters, consider who would be making the decisions
on where new CalTrain lines are to go and what parts of CalTrain are
to be upgraded and what kind of service is each part of the system
going to get and how much each of the CalTrain counties is supposed to
contribute in subsidies to it. Since CalTrain has in common with BART
the unpleasant feature of running in three counties with lots of
rather divergent political interests, how would an expanded CalTrain
avoid suffering from BART-type politics?
Newsgroups: ba.transportation