• Light rail maximum train length

  • General discussion about railroad operations, related facilities, maps, and other resources.
General discussion about railroad operations, related facilities, maps, and other resources.

Moderator: Robert Paniagua

  by TransitGeek
Is there a practical limit to the number of cars use can run in one light rail train set? Most agencies seem to use two, and I've heard of four, but I don't know if it can go higher.

I am thinking particularly about Boston's Green Line which is operating at or above capacity for most of the day. Obviously you would need to extend platforms, but what other issues would longer trains create? And does it make sense to extend trains to maybe 6 of 8 cars, or just blow it all up and built heavy rail?
  by The EGE
If you need an operator per car, then that is a very big cost. Systems like the MBTA are limited by station length, especially at grade crossings - the B and C lines cannot possibly run more than 3 cars trains regularly.
  by Robert Paniagua
I think the most longest light rail consist that Ive seen anywhere in North America is Boston's Green Line 3 cars trains. Toronto's Light rail trtains are no more that two trolleys
  by ExCon90
Unless things have changed, the San Diego trolley regularly runs 3-car trains on the Blue Line to San Ysidro, which in rush hours are expanded to 4 when leaving the street running at 12th & Imperial (running 4-car trains from or through downtown would block cross streets at stops). Northbound they drop the rear car at 12th & Imperial, and it goes back on a later southbound. (Of course lengthening platforms in San Diego wasn't much of a problem since they're all out in the open). Lengthening Green Line platforms in Boston might result in a situation where the distance from the platform end at one station to the beginning of the next would be less than the length of the platform itself. If memory serves, San Diego has only one operator per train; the operator releases the doors at each station and the passengers press a button to open the door they're at.
  by jwhite07
Sacramento regularly runs four car trains.

Other than platform lengths, as noted above, another common limitation on LRT train lengths is the length of city blocks in a street running environment (Portland MAX can operate only two car trains, and I believe the same constraint is the case in Baltimore, because of short city blocks downtown). The capacity of the traction power system is also a factor - considerable upgrading was necessary to allow regular operation of three car trains in Boston, because a triplet of Type 7s drawing maximum amps with air conditioning running full tilt was once enough to trip substations.

Mr. Paniagua, TTC's CLRVs and ALRVs are no longer equipped with couplers and thus operate as single cars all the time. Towing, if necessary, is accomplished with the use of a towbar pinned to the anticlimber. I do not know whether the new TTC streetcars are equipped with couplers.

SEPTA's City-Surface cars are equipped with long-shank unfolding couplers, and in the rare instances SEPTA has tried to run them in two car trains, they found it necessary to attach safety ropes between the cars. The length between the cars was apparently enough that people often tried to climb over the couplers in between cars. I think the same kind of folding coupler was originally installed on some or all of the TTC cars, and was likely removed for the same reason. The "Red Arrow" Kawasakis have a more standard design of coupler.
  by mtuandrew
The Metro Transit LRT system can use three-car trains as well, but the cars themselves (Bombardier Flexity Swifts and Siemens S70 Avantos) are double-articulated with a short center section. Each Bombardier car is 94' long, and I think the Siemens units are similar, for a total length of 282 feet. That's probably the practical limit for most LRT systems, I'd suspect.