So, I’ve been doing some railway=interlocking relationships over here in leftpondia, and have run into a rather curious situation that I can’t find any tagging guidance for. Basically, I have two railway=signal_box objects (signal bungalows/huts/cabins, really, as they’re both remote controlled from far, far away) that control parts of the same interlocking, as it’s a diamond crossing between a rather busy main line run by one operator and a much more minor line run by a different operator, and each operator has control of their own signals there.
The two pieces of the interlocking do talk to each other, of course, but neither of them has complete control of the interlocking plant by itself, which raises the question: which bungalow gets treated as the “master” box and which gets treated as the “remote”, or should both bungalows simply get tossed into the interlocking relationship without a role, even though that’s not documented as being supported? (Oh, and if you want to work on it, you have to ask both controlling dispatchers/signallers for foul time)
You mention certain things as being “not documented as being supported”. I’m having difficulty finding the documentation in general. Taginfo also isn’t aware of a wiki page for railway=interlocking.
The railway=interlocking relationship is documented on the wiki as part of the OpenRailwayMap tagging schema. However, the documented schema only supports 1 roleless member in the relationship that denotes the primary signal box.
If it’s a tag that’s only really used by one data consumer then their interpretation is probably going to be the driver for what ‘works’. It might be worth asking on their github page.
I think I might put a few stubs in the wiki for some of their more common “in use” tags. At the moment it’s not very easy to find the documentation when all you have is the tags.
Oddly railway=interlocking only appears to be tagged for approximately half of these relations, so they seem to be used for other things as well. If anyone knows what these are it would be good to get them on the page.
I must say I find the previousrelation=controlled_area much more intuitive for what railway=interlocking seems to be trying to represent.
In my quick check of a few of these relations when I was looking for non-“interlocking” applications I think they seem to be stretching the definition of public_transport=stop_area far beyond what it appears to be for in its definition, but that’s an argument for another time.