Hello everyone,
I have made my own physics train system which I coded myself and runs entirely on constraints, so not much scripting other than detecting throttle, most stuff so far are emphasized on the train itself.
Right now it seems I have a very huge issue of trains having a vibration issue. I do not want to use gliders at all so that’s out of the equation, instead I am trying to work with solely constraints.
The train can seemingly accelerate high up hills with zero issues and run on curves of 200m radius, but if you watch this video I have uploaded below, it seems that the train has a tendency to vibrate in motion.
All 3 cars of this medium rail vehicle seems to shake. The main issue is probably something else I can’t figure out.
Even when the train “idles” at a station, this issue persists:
If anyone has any idea to help solve it, do let me know please, thank you. 
Best Regards,
QizheTheNSCDev