Train switchbacks don't work

If you set up a "switchback" for a train to use, it can't pathfind through it. If you manually direct it onto the first leg of the switchback it will then auto-navigate to the other part of the switchback, but it cannot do it automatically. I could have swore I submitted a bug report for this already, but I can't seem to find it.

Scenario:

1. Set up a track that zig zags where the train enters a leg and then reverses from that leg into another leg different to the one it entered from
2. send the train along the route
3. Note that the train refuses to move because it can't pathfind from the source leg to the destination leg.

sample save: (its the crude oil route)

save.save

Files not imported: save.save

This is working as intended. We don't pathfind through switchbacks. Players need to build a station to make this work.