[openrailwaymap] Tagging decision: ebicab, atc, convel, zub123

This tagging discussion is relevant for PR703 so I added a copy of this email there. Dear community, EBICAB is a trademark for on-board equipment, from a specific supplier (Bombardier). The entire train protection system contains some other things [1]. The entire system is called ATC in Norway and Sweden, while Portugal calls the exact same system CONVEL. To add more confusion: Denmark calls [its own system](https://de.wikipedia.org/w/index.php?title=ZUB_123) ATC [2], while it is incompatible with the Norse/Swedish/Portuguese system. Also the current situation in OSM is different than you currently envision (with adding the `railway:ebicab=700` tag): in the past I already added `railway:atc=yes` tags to relevant tracks in both Portugal and Norway with the same purpose. You also envision the `railway:ebicab=900` tag (probably for Finland) while Finland uses the `railway:jkv=yes` tag with the same purpose. Denmark is a bit of a blank slate, because Denmark doesn't have train protection tags yet. OpenRailwayMap has 2 options: 1. Render compatible systems     consequences: a) we proceed with this PR as is b) we have to retag Portugal, Sweden, Norway and Finland (I'm willing to help) c) we should create an additional PR to also render `railway:zub=123` d) Denmark should be tagged with `railway:zub=123` 2. Render local names     consequences: a) this PR should change to `railway:convel=yes` b) we should retag portugal from `railway:ebicab=700`/`railway:atc=yes` to `railway:convel=yes` c) we need an additional PR to render `railway:atc=yes` c) Denmark should be tagged with `railway:atc=yes` I am in favor of option 1, because my opinion is that the goal of ORM signalling layer should be to show compatibility. Best regards, JJJWegdam [1] Overview of train protection systems in PT, DK, NO, SE, FI as far as I currently understand them [2] Danish border, seen from Germany. Note the start-of-ATC signs.