This loco and many like it, e.g. 2035, have linkages on the side that are just for looks, except for driving smoke. All the wheels are connected through spur gears one one side. other side has pressed on wheel on each axle. So this is what makes my question so puzzling.
The engine ran great for the couple years I've had it. Coasting great. Very free-wheeling. But suddenly it slowed down and stopped. It was pulling about 10-12 cars. Examining it I found binding on the left side linkages in one spot during rotation. The left side has the geartrain. Taking it apart one link at a time, I found the side rod was binding. Looking at the wheels, the rear wheel seems to be out of phase with the other two by about 20 degrees. See pic. Probably the cause of binding since removing the rod freed up the wheels. I have no idea how the wheel moved (if it did). No gear teeth show any damage. No wheels seem loose. All are meshed together with gear teeth. I have no way of pulling and reinstalling the wheel so I elongated the holes in the side rod for more clearance. So this worked, no more side rod binding. However, with all the linkages reassembled, I still had binding in a different spot. What was binding now was the eccentric rod post to the side rod. Again due to one wheel being out of position, forcing the eccentric rod post into the side rod. Another elongation of the center side rod hole fixed this interference.
So it runs fine now, although I am shy about running it under much load.
So I solved the problem, but am still puzzled how this could happen after 75+ years. Any ideas?
Thanks, Bob
