Hello,
I got a hold of one of these same type of HI-FI athearn drive A & B units. Mine is still waiting for rubber bands. I've heard that these locomotives don't pull very well, due to their rubber bands.
Mine is from the 50's or 60's, motor still works. I'll get her fixed up and running down the line. I even thought about, just pulling out the motor and making dummys out of them.
Patrick
Beaufort,SC
Dragon River Steel Corp {DRSC}