I wanted thank you for your suggestions. I spoke with a lionel repairman about this 2020. he had a similar problem and and advised me to place the engine on blocks so the actual drive wheels would be suspended. then run jumper wires to the engine and while it was running in place, use a toothpick and stick through the back of one of the brush tube rear acces hole and apply a little more pressure to the motor brush. if the engine picks up speed in forward you must adjust the motor spring, and my engine responded exactly as he mentioned, if this did not work i would have tried the other motor brush. You live and you learn. take care
That is a good troubleshooting tip. Thanks for the post.
Earl