I just bought Planet Coaster and I've built my first roller coaster. When I test it, the wagon will move a little and then stop moving, if at a ramp then it'll just roll back. I just don't understand this. I have done everything as basic as you could, I even tried making a roller coaster that just goes in a circle but it will stop after some metres too. What am I doing wrong? Does it need electrical power/where do I set this up? I've read a similar thread but nobody knew an answer so I find this very frustrating :/