Such a silly mistake, it seems to be working after correcting the misaligned signals in the bottom right...thanks for spotting the issue!

ah, they have to be exactly aligned? it still works sometimes (that the train chooses the empty slot to exit through)

Why is the train in the picture choosing to go for the path with a red train signal (top one) instead of the bottom one which has a green signal? This is messing up my train network since it blocks all trains until I manually move the train in the top. It's not limited to the case in the picture, so...