On
The Mechanism
Since many people were interested: Here is how the mechanism works:
The axis that connects bogie and wagon is not vertical but slightly tilted forward. When it turns that forces the wagons to tilt into the curve.
I built it in Studio so that you can get an idea of the mechanism:
Only one bogie per wagon can include this mechanism: Otherwise the train would derail in S-shaped curves because then one bogie would make the wagon tilt to the right while the other one would make it tilt to the left.