Invisible engine for leaving wagons on a side track (UPD)

[vinaximus]

I think u can extend the function of the invincible engine. It should be refitable to different speeds. This way players can limit the speed of a high speed engine, on a track with slow trains. This means no tottering trains. Great isn't it?

[Kogut]

It may be solved using "speed signs" from Chill's patchpack: http://www.tt-forums.net/viewtopic.php?f=33&t=47622

[Level Crossing]

Or you can use the NuTracks newGRF.