Ways we could make trains safer and smarter

Re:Ways we could make trains safer and smarter by dheera on Monday May 08, 2017 @06:33PM (#14296249)

I've always wondered if, in the age of high-speed bullet trains, it is possible to use the pair of rails as a transmission line, send a pulse down the track, and measure the distance to the next obstacle by the reflection.

Of course they use the rail as an electrical ground, though, which could be an issue.

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Re:Ways we could make trains safer and smarter by AnimalMuppet on Monday May 08, 2017 @07:26PM (#14296513)

I don't see why you couldn't. You're basically describing a time-domain reflectometer.

But it is correct for you to say "to the next obstacle" rather than "to the train". The next obstacle could be a switch, or perhaps a line welded on for the signaling system. It could even be a broken rail.

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Re:Ways we could make trains safer and smarter by NamTaf on Monday May 08, 2017 @09:44PM (#14297145)

Track joins mess with that sort of thing. They serve two purposes: 1) to insulate between sections of the aformentioned short-across-rails signalling system, 2) to allow for the thermal expansion/contraction of track due to temperature. Even without 1, you still need 2 and that will interfere with sending any signal down the track.

The problem is that detecting that serves no purpose, and you need to detect past those joins for it to serve a use.

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