It would help if LuaATC tracks and operation panels could send ATC
commands to trains, which are not on a LuaATC track.
The trains have an unique ID, so identifing should be no problem.
To prevent trouble the command should only be legal, if
-the train (any owner) is on tracks in an area with the same owner as
the area of the LuaATC track/operation panel
- the train (same owner *) is in unprotected area and not under control
of interlocking from another player
same owner: it should be possible that one player allows other
player(s) to control his/her trains remotely (eg: freight trains from
several players and operated by one player)
IMHO it would be better if we allow trains to execute LuaATC themselves (i.e. LuaATC trains).
Partially implemented in 6135f8a2. No access control for now, as this
appears very complicated and LuaATC has security issues in many other
places.