Hi again guys. Sorry for the delay in responding to your inputs, and my final findings and resolution. In-between , I had an operation on my eye, and have been a little bit out of commission!
The findings were somewhat surpriaing. After spending much time studying the probem, I began suspecting the trolley pole. It just seemed too big in diameter (wire size) to fit? I had a second trolley without a pole and swapped parts like the plastic pole holder, and the vertical pinion gear shaft. Nothing worked. I looked at the parts under magnification and found that there is a grove inside the hub of the plastic pole holder opposite the slot in the same piece. I also noticed their was a "flat spot" in the top vertical pinion shaft. These must be lignned up when you push the pole and it's bracket down on the shaft. It is the method of keying the pole to the for and aft position on the trollye corresponding to the bumper position. If it is off position at the end of the bumper travel position, you must re-time the rack and pinion on the bumper slide switch. After fooling around with it for over a week, I discovered another trolley pool in my "junk". It indeed was a smaller diameter wire, and readily fit in it's place between the plastic pole holder and the vertical pinion shaft. Problem solved. It now works like a charm. Since I had the trolley disassembled, I lubricated the motor, and wheels, and gears. I also cleaned the commutator surfaces and slots. It now works at a very low voltage and has enough inertia to change direction at those low speeds. I Did indeed have a replacement trolley pole that I picked up somewhere that was too large in diameter!! I wonder if that vendor knows the grief he has caused by manufacturing and selling bad parts ??
Thanks again everyone for their help and input.
Paul