You will need to add supports to the steering hubs and to the "gear2" first layers... you should be able to print the rest of the parts without supports.
I recommend printing the gears with special care, maybe lower speeds and accels, 0.1mm layer heights and pay special attention to the perimeters start/end points to ensure they are in the inner of the teeth, not the tip.
Hi there! I'm an individual who has been designing and playing with RC cars and Slot cars for some years. Take advantage downloading and playing with my designs :) Let your screen rest for a while building and playing physically!