Why not just use the AngularVelocity of the wheel hinges to move it?
If your MotorMaxAccleration or MotorMaxTorque is too high it’ll cause the cart to do strange things.
If your cart is very light it’ll cause physics issues as well.
Think of the cart in the real world if you are using Constraints. Mass of the frame or the wheels affects how it’ll handle. The amount of power as I mentioned above will affect how it handles. The suspension will affect it too. If the cart is really short physics will tip it over.