3 ms·
Railway signaling works based on whether something is there, not based on whether it should be there. If the freight train stops, then the signals for the pass
by AnimalMuppet 3y ago
Railway signaling works based on whether something is there, not based on whether it should be there. If the freight train stops, then the signals for the passenger train will tell it that it cannot proceed.
I don't know anything specific about Poland's rail signaling, but they can't have messed that up. It's written in blood.
- KptMarchewa 3y agoThere's a way but multiple things have to go wrong. https://en.m.wikipedia.org/wiki/Szczekociny_rail_crash https://en.m.wikipedia.org/wiki/Szczekociny_rail_crash
- tialaramex 3y agoWow, that's a lot of places where human error was able to make things worse. Particularly the fact that it's possible to use a "subsidiary signal" to just override the problem. The equivalent British scenario calls for the signaller to vocally inform the driver (e.g. today over GSM-R) something akin to "Pass the danger signal at caution, obeying all other signals". This may mean if there are a multiple related failures, you need to "caution" drivers the same way repeatedly - but without that final sentence the driver may ignore signals that are not related to the failure you understood, and passing those really will kill somebody. The requirement to move "at caution" meaning with the ability to stop on sight means trains under these conditions don't go very fast - they can't, even on straight lines in broad daylight you can't see far enough to go full speed on a passenger train under those rules, but it also means if you screwed up and there is a serious problem the driver under caution can see the problem with enough time to stop. It further ensures there's an incentive not to allow such situations to persist as they presumably must have for Poland to deliberately fit the "subsidiary" lamps.