Algodoo

This is nothing unusual. When you spin objects too fast, they tend to fly apart. That happens in real life as well as in Algodoo. Also, you created a large number of boxes (I count around 50) which you attached together with a very large number of randomly placed axles (over 100). So, it's no wonder that this large clump of nonsensical objects behaves in an unusual fashion.

Xray, set the angvel of all the boxes and everything to 0. It seems to accelerate itself.

No, I'm not going to waste my time on a nonsensical bunch of random objects that were stuck together with a large clump of randomly placed axles. Maybe at one time you wanted to make some sort of a bridge, but what you ended up with is just a clump of nonsense objects.

I suggest that you try making a scene that people would enjoy playing instead of making scenes like this one that chaotically explode or fly apart. You made some great scenes in the past, so I know that you can do it!

Thanks and oof.