Very useful, just checked mine and they're ball race fitted.
Wouldn't have told you to bother with them if they had the bronze bushings.
I wish I had thought about using the tail end for the drive rather than the gear head end. I should have figured that out. And yes, you can fix the motor by either end, or both if you really wanted to. The one issue with essentially turning this gear motor into a regular motor is that the motor cover on the gear head end is the larger diameter to accept the housing. A regular motor would have a cover on that end that matched the diameter of the motor body. It matters because the motor body will fit inside most if not all O scale locomotives including hood units like sd40-2's or 08 shunters. On the other hand, the diameter of the gear head on these units is often too big to fit inside some of the plastic O scale shells with their armor plate wall thickness. Could you take the gear head cover off and replace it? You could, it's screwed on from the other end. I've never had one off because I couldn't break the screws loose, I presume they are set with a thread locker that will require some heat to break. I've considered contacting Pittman and seeing if I could get some replacement ends, but the other solution would probably be to turn new ones if the desire was strong enough. Actually the proper solution would be to keep an eye out on ebay and just buy regular motors of the right type, ideally ones with shafts at both ends, when they finally turn up at the right price. It's bound to happen eventually. But that's too simple, so nah.
No question that the motor has enough power without the gear reduction, it's actually how most of them have been used over the years. The gear motor implementation is really the anomaly, not the other way around. Actually it's not accurate to say the motor is fine without reduction, because all the gear head does is change where the reduction takes place. If it's not at the motor, it's at the truck. And no, you probably don't want reduction at both the motor and the truck, at least not full reduction in both places. It would take you a long time to get anywhere.
The premise behind the use of the gear motor is that all the reduction happens at the motor, so all components downstream are spinning at a 1:1 rate, much slower than they would be otherwise. Theoretically that means less noise than otherwise. Gearing at the trucks is accomplished with 1:1 helical gears at right angles. I'm not sure who started using it in model trains, but I know that Jay Criswell further developed the idea and uses it for most of his drive conversions.
My issue with the system is that it requires two drive shafts if powering trucks on both ends of the motor. There is the output shaft on the gear motor, but that needs to transfer power to a jack/cardan shaft which then powers the trucks. By necessity, those two shafts have to be one above the other, which means the motor must move up, which means less room inside the hood for any required boards or speakers. My goal is to have a low-profile drive which has the motor as low as possible, thus leaving as much room as possible in the shell above. The conclusion is that for my wants, I will need a double shafted motor that fits within the length of a fuel tank, with all reduction at the trucks. Unfortunately, that means that all of these gear motors I've acquired over the years are not suited for my purposes.
If you're doing a loco with a full width body, especially driving only one truck (sound familiar to anyone), or doing a steam locomotive with a single gearbox, then these motors would be great choices.
