A non-stop MRT system has been proposed as a solution to all that time- (and energy-) wasting starting and stopping that trains do.
Taiwanese inventor Peng Yu-lun imagines a main track with a large commuter train that does not stop. The train is serviced by smaller train cars that drop off new passengers while picking up those who wish to leave the train.
Take a look at his idea in the following video.
(Non-stop MRT system video in Chinese)
Although Chinese officials look interested, it's hard to believe that this is a workable solution. Science fiction writers have worked on the generalized version of this problem; let's see how they do with it.
A train that does not stop is essentially a long line of seats that moves at a constant rate of speed. This is the idea behind Robert Heinlein's 1940 classic The Roads Must Roll. Read how Heinlein proposes to get you onto the "train:"
They glided down an electric staircase, and debouched on the walkway which bordered the north-bound five-mile-an-hour strip." Have you ever ridden a conveyor strip before?" Gaines inquired. "It's quite simple. Just remember to face against the motion of the strip as you get on."
They threaded their way through homeward-bound throngs, passing from strip to strip...
After passing through three more wind screens located at the forty, sixty and eighty-mile-an-hour strips, respectively, they finally reached the maximum speed strip, the hundred mile and hour strip, which made the round trip, San Diego to Reno and back, in twelve hours.
(Read more about Heinlein's rolling roads)
The pedestrian version of this idea is a slidewalk.