I recently finished my third 18 ton GrandtLine 0-4-0 porter. This time, I used an On30 conversion kit to make the locomotive On3. The kit basically includes two frame spacers, two helical gears (needed due to the narrower frame) and a new rear frame/ashpan front (the frame inserts into this piece). These gauge conversion kits were also made for On2 and I hope to have another conversion done by 2022 for the On2 module. We'll see.
So, after disassembly, messing around, I determined that the bind was in the drive and by moving the motor up and down slightly, I could eliminate the issue. So, I glued the motor in and reassembled it. Still a little bind in reverse but great moving forward. A gearbox would definitely eliminate this issue. If someone out there could develop a gearbox for a different motor, I bet San Juan (new owners of the GrandtLine moulds) might be willing to produce these again.....otherwise, I doubt it.
Regardless, a great looking and sounding engine that is fun to build and a pain to get running well. Maybe the next one will go easier?