Background is a issue asking to render this in OpenRailwayMap: https://
Everything following is just my understanding of the German Wikipedia article,
I don't have any original knowledge about these things, so please correct me
if I'm wrong.
So, previously we had the "LZB-Blockkennzeichen" (LZB block marker) in
Germany, which has been renamed to just "Blockkennzeichen" (block marker) in
2012. This is a black circle on a white square sign, with the block number
inside the circle: https://wiki.openstreetmap.org/wiki/File:LZB-Blockkennzeichen.jpg
A new version which comes from the ETCS world is just a black arrow on a white
square sign, with the number on a separate sign below it. This is basically a
monochrome version of the ETCS stop marker: https://upload.wikimedia.org/
From what I can see these signs are basically identical in meaning, and there
exists no tagging for the new version of the sign. I think it was a genius
idea to add the ":shape" subtag (*cough* *g*), and this could be easily used
For the time being we must treat a missing :shape for the German signal as
Afterwards we can start adding a rendering for this, which should be easy as
it's just a copy and color change of the "ETCS stop marker" image.
Since this signal comes from the ETCS world it is likely in use outside of
Germany already, the German wiki page e.g. refers to Swiss "ETCS-
Standortsignal". The question is: how is the tagging of this type of signal in
other countries? Do they also use different shapes or does only the arrow form
exist there? Would be nice to know as that could be added to the rendering
rules at the same time.