Algodoo

The max speed is about 25 rad/s, or about 250 rpm. It has pretty much unlimited torque so it can climb over anything. To adjust the torque increase the repulsion of the light gray box. It uses the the variable scene.my.magnet.

By making the attraction value a variable and using a k-probe with some thyme one can make a dynamic engine, making it possible to go at the same speed at all times even under heavy loads.

Credits to conundrumer for the circle gears.

You can use it in your scene, just credit me.