Railway 'roundabout', what's wrong here.

[taiiat]

looked in the stickied Train post, this strangeness doesn't seem to apply, i don't think.

_

so what i'm trying to do here - the red line shows the only path the train can currently take. but the train should be able to take the two possible routes in Cyan?

i've checked the corners and the tracks are all connecting AFAIK.
but the problem remains. for some reason, the Train can't effectively take a 90° left turn without entering the loop for some reason.
but i can't see why it can't do it.

it's not really the end of the world, the train can 'just' enter the loop, and circle around, leaving once it's done a 360° loop..... but i don't see why that's necessary.

[DaveMcW]

You can't make a perfect double S intersection (just like you can't make a perfect circle). You need an extra diagonal track in the middle.

Remove the left and bottom tracks to better see what is wrong.

[taiiat]

You need an extra diagonal track in the middle.

ah. more rebuilding of everything, again - but i'll do that.