Problem with rigid body vehicle rig


since quite some while, I work on a rig for a tracked vehicle (Mark IV tank). I used McGavish’s splendid tutorial on YouTube as a reference:

Now there are some important differences between a vehicle as modeled by him, and the Mark IV tank. The most prominent are the rails, which prevent the track from sagging below the tank, as seen here:
(sorry for the German annotation, it demonstrates the flanges on the trackframes which act as rails, and the counterpiece on the inside of the track links).
At the top, there are no support rollers but rails on which the track glides along. The road wheels are not visible and do not need to be animated.

Now here is the rig I came up with:

It uses a large solid for each trackframe. On its top, the track is supposed to glide, and the bottom acts as bounding box of all road wheels. For the rails holding the track links to the underside, I use a number of cubes which should support the track links from below. My initial trials with mesh rails on the sides of the track, more like on the real vehicle, did not work, as the simulation became unstable immediately.

To prevent this fake rail system interacting with the ground, I use two collision layers, one for the ground and one for the rails, with only the track links acting on both.

I got it to a point where the simulation is more or less stable, but the crazy thing is that the vehicle now climbs into the sky at first, and then falls back down to the floor. Afterwards, the same repeats, until the track system becomes unstable and explodes.

Does someone spot the mistakes I made? Where does the jump originate? I tried to increase the vehicle weight to minimize the effect of counteracting momentum from the track to the vehicle, but this did not work either.

Any help would be greatly apreciated!

Best regards,