Indicate train stop invalid placement

[sillyfly]

Currently, when a rail signal is orphaned from it's rail it flashes to give the player indication it's malfunctioning.

The train stop has no such functionality, so players may remove the rail the stop was connected to and not realize the stop is no longer connected to anything.

I suggest adding a simple flashing animation, similar to the signals, to alert the player when a stop is no longer in a valid spot.


Example: this thread shows the problem.