DON'T pull the wheels unless you have the skill to quarter them when you put them back! On these model locomotives, one axle is powered by the gearbox, and the rest are powered by the side rods. The crankpin locations have to be properly quartered, or the siderods cannot transmit the power, ie they will jam up.
The entire axle should come right out. I have a few 3rd rail 2 rail locos, and the bottom plate on the frame comes off allowing the axles to be removed. The gearbox has to disassembled to get that axle, but it should have screws on the bottom side.
However, you still have to remove the rods. and then reinstall them. These have to go back accurately becasue the side rods transmit power to the non-geared axles.
All that aside, I can pull 25 2 rail cars on level train with my little 3rd Rail H6 2-8-0s. If the 3 rail version will do the same, why do you need traction tires?
