Our area is planning light rail, at enormous expense, supposedly to reduce traffic congestion. But the thing is expected to average only about 20mph, stopping every mile, even though it can go up to ~40mph between stops. There other benefits and difficulties, but it doesn't look very attractive in the net - it needs to be faster.

There is a way you could average twice as fast for rush hours - 40mph - making the system more attractive for commuters. This will sound rather complex - but computer control should handle it well enough.

Start by building the light rail trains out of independent, computer controlled "dockable" cars. During rush hours, passengers wanting to take an express ride - stopping at no stations before their destination - would get on a docking car on a side track at their closest station. As an express train passes, the car would accelerate out of the station, swiftly catch up and dock with the express.

That would be it if everyone were going to the same place. Since they aren't, design the docking cars to have doors on front and back, allowing passengers to change cars once the car has docked with the express train. Passengers wishing to get off would remain in (or move to) the rear car, while passengers wishing to remain on the express would move forward. About 2 minutes after it docked, the rear car would undock and slow to stop at a station 2 miles from where it started.

If the express moves at a constant 40mph, it would pass two stations (separated by 1 mile each) in three minutes. This should be adequate time for a docking car to catch up, dispatch and load passengers, detach and slow to roll into a station - having skipped one intermediate station.

Between express trains and between rush hours, docking cars would be used as locals, shuttling back and forth between a few stops - so if you end up one station away from where you want to be, you need only wait a few minutes for a local to the station you wanted.

If you rode only the locals, you'd average about 12mph with stops, but if you aren't going far that won't matter as much as the convenience of frequent arrival of cars.

(SkyTran is a better idea, but it hasn't been reduced to practice yet, so there's no way cautious government types will go for it.)
-- TomRC, Oct 21 2002

SkyTran http://www.skytran.net/
What I'd really like to see... [TomRC, Oct 21 2002, last modified Oct 04 2004]

Packet switched elevator http://www.halfbake...switched_20elevator
Some similar concepts, but applied to elevators instead of trains in this idea by [mgrant] [krelnik, Oct 21 2002, last modified Oct 04 2004]

And I thought this was my own original idea... I was just about to post it too!

This idea has the additional advantage that the train tracks can be better utilized because the trains never stop. Usually subways have to keep at least a minimum distance between trains because of the unexpected delays that come when the trains stop and people are slow getting on or off the train. With a train that never stops, there's a reduced need for this "slack" space.
-- TrevorS, Jul 29 2003


I like this idea, I think it has been proposed before, in "shuttle trains". Not sure who was first but never mind.

To my mind this solution is overly complex why cant I got to the station and catch a train directly to my destination without having to go through a dangerous high speed transfer.

It seems to me that there should be one "smaller" train at each station for every other station. ie a "modified tube" arrangment as I have described already.
-- madness, Jul 31 2004



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