I’m starting to think seriously about the drive train for 622. On #10, I built my own gear box, which enabled me to model the full backhead and floor of the cab. That’s all very nice when you take the roof off, but most of the time you can’t see it.
For 622, I’m considering the Northwest Short Line 28:1 Idler gear box kit, which should enable a 12×24 motor to fit horizontally in the boiler. You can just see its purple shape in the lower half of the cab and behind the rear wheel. Painted black, with a crew in place, and some distracting backhead detail, it should disappear.
With a NWSL gear box, I lose the easy opportunity to create a torque arm. So, I’m currently grappling with how to mount the motor. I’m open to suggestions!