Shay geared engines were commonly used for logging operations where loads were heavy, speeds were low and track was poorly laid. They had the cylinders vertically mounted on one side of the boiler to drive a crankshaft which powered all the wheels. This one doesn't power all the wheels, the tender contain a 9v train motor but the pistons cranks do move in speed with the engine through a geared 9v technic motor taking power from the train motor.
That's great all hail the master of shay class locos. I had an idea about making it work with actual piston movement but it looked wierd so I scrapped it. Now since I have money to buy 9v stuff it will make everything much easier. I only have the old rc diesel bases to power my trains. I had made a 4-4-2 Atlantic type and to power it I had to use the diesel base and have a " double length tender"