Please stay on-topic. Performance is a known top priority for the devs and you including that matter in another conversation is off-topic and adds nothing to the discussion.
As for why I’m actually posting in this thread.
You’ll all be happy to hear the first step to more station customization is in the works. The patch notes note one of the things they’re working on (hopefully in the next release; also on the way to waypoints) is station platform selection for lines. This should allow for much more intricate networks. Divided platforms is a simple step from there.
A train servicing one line, and then splitting into two trains to service two different routes is probably a lot harder to achieve so I wouldn’t expect this for some time.