rail damage and rail movement

[ComradeP]

Rail movement through a rail out hex isn't possible, but units can leave rail mode, move to a non-damaged rail hex and switch back to rail mode as long as rail capacity is available.

There's no check to determine whether a rail hex is or isn't operational aside from the "rail out" status. You don't need to be able to trace a path of undamaged rail hexes to the edge of the map or something like that in order to switch to rail mode. It's possible as long as rail capacity is available.