Factorio Forums

I've been playing factorio for a while and I've always had difficulty making a train line with a train with 2 locomotives, one behind and one in front... the game doesn't seem to support this type of action, because the train signaling system is buggy. .. because when I put him to go to a place and another signal for him to return, the game cannot understand and starts having problems understanding this type of action
suggestion: greater feasibility between creating trains with 2 locomotives, being able to choose which locomotive will move at a given time. improve the signaling system to recognize the return and departure of the train.

Trains can do this probably since their introduction, at least for longer than I'm playing Factorio.
Please post pictures of your setup or the save, there's probably an error in your signaling. But note that trains will only change the direction of travel when leaving a station (and when they're initially switched to automatic).

My guess: You've put up some (chain) signals on your track, but did it wrongly. If you want your train to go back and forth, signals must be on both sides of the track, otherwise the rails will be regarded as uni-directional. Also, the rail blocks must be the same in both directions, so you must place the signals exactly opposite of each other, without offset.

You might find this guide helpful in getting the signalling to do what you want:
viewtopic.php?t=53937