>> Yeah, but how do you distinguish that?

> By enumerating the tracks?

How do you distinguish that the <2km away detected moving train runs on your track on not on the one directly besides you?

> Trains are captive to a particular track - they can only change tracks at specific pre-determined junctions.

Yeah, but you do not know which one it runs on. Your entire point is that you do not trust the information the infrastructure knows. If you do allow to use information from the infrastructure, then why not use the sensors that already exist along the whole train network? It's also very unlikely that there is something electrically connecting the two rails of a track, that you would like to run over. So why wouldn't you trust that information, but some vague GPS signal?

> we can statically determine

But the current state of the art is, that you deterministically and provable know where a train is. Why would you use a more expensive, less safe system? The current focus to reduce errors in computing train conflicts is to prevent random bit flips due to radiation at the same time in three different computers running different software.

> I feel like you are intentionally trying to turn this into a spherical cow situation

The situation where you proposal makes sense, but the current system does not, is a spherical cow situation, that's my point.