So far my favorite mindfuck with French railway signaling: one of the common signals is called a "square". This, of course, is because the signal in question never has a square shape.
(it used to, in the days of mechanical signals, but in modern times it's an oblong set of traffic lights)
@phrawzty In this case, it does just mean "square", due to the shape of the old mechanical signal aspect :)
Later on, for better night visibility, two red lights were added next to the square... And today you just have the lights and not the square.
(source: "La Signalisation Ferroviaire" de Retiveau, Chef du Département de la Signalisation a la Direction de l'Equipement de la SNCF dans les années 80)
Okay new favorite signal: the visual hand signal for "stop" is an unfurled red flag held up, or arms raised, or arms waving vigorously, or waving any object vigorously.
Basically, a red flag and/or any gesture vaguely indicating panic.
@aussiegeek Sort of, yeah. The meaning is just "a train is present in this block". Depending on the type of block discipline, sometimes a train is allowed to proceed into the occupied block in "marche a vue", i.e. no faster than 30kph and being prepared to stop rapidly.
On the flip side, a double red signal always means "do not pass", no matter what type of line you're on.
@aussiegeek The line I'm looking at uses BAL signaling (https://en.wikipedia.org/wiki/French_railway_signalling), which is reasonably normal red/amber/green automatic blocking. Green = proceed at speed, amber = be prepared to stop at next signal, and then either a double red for "stop until the signal changes", or single red for "stop, but then depending on other placards and the rules for this particular line, maybe proceed with restrictive rules"
@aussiegeek In this instance, seems like most of the BAL signals on this route are type F, so a single red means: make a full stop at this signal. After that, you may proceed through the next block with a 30kph speed limit and "marche a vue" rules (reduce speed as needed so you can always stop within the portion of track you can see).
@aussiegeek IIUC the idea is that these blocks are one-way, so red means either a train is stopped somewhere in the block, or it's moving in the same direction and you're just too close.
In the former case, marche a vue ensures you'll be able to stop safely when you spot the halted train. In the latter case, going at 30kph for a kilometer or so (normal line speed here is 220kph) will let the leading train get away and give you a green signal on the next block.
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