TL;DRAdd train stops that can be approached from either direction.
What ?I suggest adding a train stop entity that trains can approach from either direction. The double headed train stop should be placable between wagons and 1x4 tiles big or 2x2 so it doesn't collide with inserters or big chests or bulk rail loaders from mods. It could be either an arch like 2 normal train stops combined or just a little box in the middle of the tracks, which would fit a 2x2 size better and could keep the 2 tile alignment of rails.
The aim of the double headed train stop is to be a waypoint, not the actual station, because of where trains would stop relative to the double headed trainstop.
Can the circuit connection for the little box version be at the outside of the tracks on both sides? Would allow placing the wires so the train doesn't drive over them. Or can there only be one place per entity where each wire connects?
Why ?When playing with double headed trains one can either have terminal stations where a train drives in one way and leaves the other way. Or one can have stations where trains can enter and leave from either direction. The later requires placing train stops on both sides of the tracks so the train stops between the two regardless of which direction it comes from. That works well until one wants to add a train limit to the stops. For example train limit = 1. Because you really don't want a train coming in the way the already present train wants to leave.
The addition of a double headed train stop would allow placing them in the middle of the station as a waypoint. Circuit logic can then be used to allow 1 train to target the waypoint and then set the train limit to 0 until the train has left the station so no other train uses the same waypoint till it is clear again.
This can't be done with 2 separate train stops on opposite sides of the track as the decision must be atomic or trains stutter and can eventually block traffic. For a discussion of that problem see viewtopic.php?f=18&t=100181