360 degree movement in a bent tunnel

Hello everyone.

I’m having trouble getting my head around a special type of movement/pawn.

I’m trying to implement this: Ballistics Gameplay Video 2 - YouTube

I’ve tried prototyping an idea where the vehicle moves around the tunnel’s axis, but it doesn’t account for bends. I also tried to get the vehicle to be constrained to a spline going through the tunnel’s center, but I didn’t get far with it.

What would be the best way to implement this type of movement?