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Quis custodiet the custard?
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Despite being a very efficient form of
transportation, trains are very heavy and
lose a great deal of time slowing down and
This problem could be eliminated by
adding an extra parallel track running in
each direction on the most heavily
travelled lines. Passengers would board
waiting room housed in a shuttle train
running on the outer track.
The shuttle would then accelerate to the
same speed as the main train and lock
onto it. Automatic doors would allow
passengers to board and detrain, the two
trains would unlock from each other, and
the shuttle would return to the main
station to drop off the passengers and
take on more for the next train.
In addition to saving passengers time by
making all trips effectively non-stop, the
shuttle train would be smaller and lighter
than a normal train (because it only carries
the passengers for one station), and would
use less time and energy per passenger.
This idea would only work on the
highest-traffic lines -- it could probably
carry as much traffic as a conventional line
with the same number of tracks, but it
would need four tracks (maybe three if the
stations were far apart or the trains
infrequent), which is more than most
existing lines have.
shuttle loaded trains
[spacemoggy, Dec 19 2004]
||this is a veriation of how amusement parks load and unload many rides.
||This seems almost identical to 'The nonstop train' above.
||This could work on the New York subway, except there are supporting beams between local and express train tracks. That said, coordination would need to be perfect with such tightly packed stops (every 7th to 10th block or so). And how much time would people really save?
||You could take additional tax money out of the city's impovershed doughnut hole to pay for this, as most middle of the road city councils do.
||This would be exceptionally dangerous if the tains had to 'join' side by side. Amusement parks may do such things with rides that are travelling at 3mph, but if the trains had to slow down that much there'd be no point. And at 60mph or even 30mph, the risks involved would be downright nasty.
||On the other hand, a different approach might be to have trains join end-to-end. This would require that one of the trains have a telescoping 'compressor car' which would have to be evacuated prior to joining. The local trail would pull up to the express until it docked, then would switch to being pulled by the express. At that point, passengers could walk from one to the other. Once that was complete and the 'compressor car' was evacuated, the local train could uncouple and fall back.
||I see this idea as one car chasing another down the track and docking with a three foot compressable bumper.
||[mensmaximus]: That would be the basic idea. Though probably not safe enough for actual deployment, I would see this idea as being much safer than the sideways-docking approach. Among other things (1) if two docked trains are travelling along at 60mph and one of them has to emergency-stop, it will be very difficult to keep them connected. By contrast, if the two trains are solidly coupled end-to-end, stopping would be no more of a problem than with separate cars on a single train. And if they weren't solidly joined, an RF control system could ensure that the second train stopped 'harder' than the first.
||That chase car is travelling 120 mph to catch up, the lead car has an emergency stop; there may be a problem there. Otherwise, an electro-mechanical release to unlatch the mechanically latching cars after passengers disenbark works for me. If this was applied to the Taxi2000 personal rail transit, I would like it. The little cars hook onto a turbo train.
||It would be necessary that the chase vehicle have its braking system relayed to the lead, preferably via multiple redundant means. Beyond that, a lot would depend upon the design of the 'compressible' car. I don't know how much compression force a train can take without risk of derailment, but I would think that provided the speed differentials were kept reasonable it may be possible to construct the compressor car so that even if the second train hit the first during an emergency stop it would not injure anyone on either train (even if the compressor car was damaged beyond utility).
||Actually, I don't remember if I posted it here (I don't see it above) but I've often thought it might be a good idea to equip passenger trains with a 'compressor car' which would be unoccupied by passengers but would be designed to be longitudinally compressible without derailment (it would basically be designed so the force required to compress it would be just short of the maximum safe compression the train could take without risking derailment). Especially for 'pusher' trains which put the locomotive in the rear, I would expect having such a car ahead of the leading passenger car, and having another between the engine and the last passenger car could greatly reduce the likelihood of derailment in the event the lead car hits an obstruction.