No, I can't seem to get them onto the shaft. Since posting I spoke with Atlas and the project has been shipped to them. The Atlas guy said it should have a larger hole on one end, but these don't. Off they go, I'm sure they'll figure it out.
UPDATE: She lives! Atlas kindly mounted the u-joints and returned the bare motor to me. I re-assembled it all this morning, and she's running around right now, and seems as strong as it used to be. I need to clean track so I can run some proper trains and see how she does. Thank you Atlas for the great support. This on an old model many years old.
After over 50 years buying Atlas N scale (I still have my original N scale brochures from them and copies of letters I wrote, asking for help), I have never found them to be anything less than very helpful. Doug