Trainz Trouble - How to get 3 stars on all levels

Trainz Trouble is a iOS, Android and PC game where you have to direct trains to the building with the respective colour.
No, it's not rocket science but it's very fun especially on mobile devices.

I'm making a series of short guides to help those in difficulty achieve 3 stars in every level. So if you're having trouble or just want to get to know the game watch this:

Until now there's videos off all the US levels. More to come soon.