Sparking question

If all the other locos work fine, then the problem is with the ONE loco.

Are the sparks coming from the pickups or the wheels? In either case, a thorough cleaning of said pickups or wheels is in order.

next, check if something inside the loco is shorting to the frame. Can you run it without the shell?

Yep- the other locos work fine. THe sparks are coming from the wheels, not the pickup- so perhaps I can start there. I'll then remove the shell and see if that works. Thanks for the advice! 

Check to see if you have any wires that come in contact with the wheel flange, especially when the truck turns. If it is and you see sparks it has already cut through the insulation.

.....

Dennis

Wondering if the trucks are getting a good contact with the chassis, (frame), Didn't some of the geeps have a special washer that fit over the motor mount making better contact between the frame / motor  and trucks .