I have a Lionel 28613 Docksider on my bench. It will only run backwards.
I removed the shell, and found when it does run backwards two of the four large semiconductors (I am guessing they are SCR's) on the main board get extremely hot very quickly.
I disconnected the motor, and applied DC power directly to it, running the current through a Simpson 260 VOM to get an amperage reading.
With no load, and the voltage set to about 6 volts, the motor is drawing about two amps! (Could I have the meter hooked up wrong?) (Checked the meter manual, it was hooked up correctly)
I do not see or feel any binding in the mechanism.
Here is my guess:
The motor should not be drawing that kind of amperage, and needs replacing.
The forward semiconductors (SCR's?) burnt out due to high amperage.
I do not work on can motor / electronic control stuff very much.
What do folks think?