With all the talk about transcontinental bullet trains, I thought that the whole subject merited a more ambitious approach.
It’s quite difficult to accelerate a train using only the friction of drivewheels on a metal track…especially as reducing the weight of the rolling components is a good thing for fuel efficiency.
Today’s invention is therefore a railway on which a very long train runs which consists of a series of low profile, lightweight carriages (something like those trains which I’ve seen crossing Canada which take half a day to pass…except very much longer).
On top of them, a set of lightweight rails allows another layer of carriages to operate at increased groundspeed (a short train running on a train which is say, half the length of the track, will run at three times its normal speed).
This approach might be extended, given very low-cost rolling stock and in the absence of low bridges, to allow speed multiplication by higher factors.
This might make marginally more sense if the lowest layers of trains could each be replaced by a rolling, tank track-like system -nearer in length to the train on top.