It sounds as if you have a problem with the conventional train or the track upon which it sits..
Remove the conventional train from the track and then attempt the same commands from the TR screen. Move back to the ENG screen and see if the DCS engine is OK.
If it is OK, there's a problem, most likely a short circuit, with the conventional train.
If it's not OK, there's a problem, most likely a phasing or other power problem, with the track connected to the variable channel.