In a previous post I had demonstrated that the bogie often flips upside down:

Obviously, if this happened in the mountains with a full size “vehicle” there could be serious consequences. For the moment, I’ve come up with a simple solution.

In the image below you can see that I’ve added a small protrusion above the pivot point of the bogie.

Rocker Bogie Fix

In the full size version, I don’t think this would be a viable solution without the use of springs/dampers but for this early prototype it should suffice.