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Comment by codersfocus | Hacker News Reader

Rail and cars aren’t mutually exclusive. Amtraks car carrier service seems to be very popular despite how badly they manage it.

Why can’t I drive my car on a train and go cross country?

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You can afford hundreds or thousands of dollars for transporting your car by train? Putting a car on a train isn't free, or even remotely cheap. Even regular Amtrak tickets in coach class are quite expensive.

And define "very popular". I was reading an article this weekend about some Amtrak line between Chicago and Minneapolis being unexpectedly "very popular", which apparently equated to a whopping 300 passengers per day. Here in Japan, that's about half of one of the smallest bullet trains, and less than a quarter of the larger ones, and those are just single trains, which usually run multiple times per hour, sometimes more frequently than every 10 minutes. In a country of 310M people, 300 people per day doing something is not what I would call "popular".

Because it doesn't scale. A single car takes as much space as 10-15 passengers, and station times are much longer if you need to load/unload cars. Popular passenger rail systems often operate at capacity, with delays sometimes cascading into network-wide disruptions. It's often impossible to add more trains without building new sets of parallel tracks, while train length is limited by the size of the stations.

Make the rail cars intelligent and autonomous. Arrange them behind the engine in a way that the first car(s) behind the engine are filled with automobiles for the terminal destination. The following cars for intermediate 'stops', and the last car(s) for nearer stops. Let the train pass through, while decoupling the last wagons automagically shortly before the station, switching them onto some side track with on- and off-ramps, engaging their brakes, or use some system which does that in switching yards after they roll off the 'hump', let the automobiles roll off, collect the wagons and send them back with any another train travelling in the opposite direction, or whereever there is demand.

Networks..., tokens..., packets..., switches..., routers..., NOT fixed circuits.

Or just use an effing Über at the destination...

But people want to board the train at any station, not just at the point of departure. If your train is a stack, you can't support arbitrary trips without excessive delays.

Transport optimization is an established subfield of operations research and theoretical computer science. The algorithms for something like sorting railway cars are quite interesting, as they have to deal with physical constraints not present in networks and software.

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