Ok that's strange.
I started up RCT3 to film the bug... and... it didn't happen. Everything was fine...
The only thing different would be:
I closed the game down and opened it up (days later).
I developed the area where I was trying to build.
I have no idea why the bug occured. That glitchiness I've only seen with Tilt-Coasters.
I now have to locate my fraps video and purge it
I know what caused the problem. There wasn't enough track for the train to sit in the station. I needed a blank piece of track at the back of the station. ========= I needed the track at the end, otherwise the train can't sit on the track. Because the back of the train isn't on track, the game assumed a crash has occurred.