From OpenStreetMap Wiki
|Used to distinguish between different public transport relation schemes|
|Used on these elements|
|Status: in use|
|Tools for this tag|
|This key page is a stub. You can help OpenStreetMap by expanding it.
Similar pages for structural reference: Key:religion, Key:waterway.
- public_transport:version=1 for old scheme
- public_transport:version=2 for new scheme according to public_transport=*
JOSM has the ability for adding the roles stop and platform of new members automatically, but only if public_transport:version=2 is set on the relation and one of the keys bus=*, tram=*, train=* etc. on the new member.