This afternoon I fixed a Bachmann GE 45 ton Diesel which refused to operate with both trucks at once. It was new, but those silly plungers are just a pain. If any 1 of the 8 isn’t contacting perfrectly then it doesn’t run - one truck tries to pull the other. (I hear the Heisler is the same, and I know the front truck on the Railtruck is also plunger driver.)

Jerry and I took it apart per Kevin’s instructions, and I soldered wires from the pads on the truck to the contacts on the loco, as you can see. I kept the position the same - I even got the red-black right on one truck.

Oh yes, the instructions from Mr K:

The plungers are crap. You’ll want to hard-wire the truck to the loco. There’s room to put a small 4-pin plug at the top of the truck if you want to make things detachable.

To get to the trucks, pull the body off. You’ll need to release the fuel tank first. This exposes the 6 screws which hold the cab in place. There are then 2 crews at the ends of the two hoods. You’ll find two elevated PC boards under each of the hoods, then on the floor, a smaller PC board held to the floor with screws. This is what carries power from the trucks and to the motor. Keep track of those wires. Removing this board exposes the screw which holds the trucks to the chassis. Remove that screw and the trucks drop out.

On the truck, you’ll see 4 open contact areas on the PC board. I’d have to check to remember which two go to the motor and which two to the track, but they’re opposite each other—north/south for one, east/west for the other. You should be able to solder to those pads without too much trouble, though you’ll need a thin tip on your soldering iron to reach through the openings.

In fact there was little need to keep track, as on this loco the boards were marked: motor-1,motor-2, con1, con2. I just threaded new wires through the plunger holes and reconnected them to the board where the appropriate plunger used to be. I left 1" or so of wire under the floor so the truck could swivel.

Its been a busy week. Not only finishing the drive train on my Railtruck, I helped Jerry replace his cracked std Railtruck back axle gear with the one off my truck, and then tried to deal with the plunger pickups on his front truck.

The metal bars I arrowed are the holders for the wheel pickups, which you can just see behind the wheels. You can also see I soldered wires to the contact pads in the body around the pivot. We couldn’t persuade solder to stay on these bars, and I didn’t want to take it all apart. The center screw holds on a cover over the pickup extensions, so we spread as much wire under that as possible and screwed it back together. It seems to work.

Then we got to work on his Heisler, which has the same useless plungers on the top of the truck. The back truck is easy, as the pivot is under the cover under the PCB under the coal. The cover has the silly spring arms to contact the plungers, so if you release the truck and take the cover off the wiper plate on top, you can solder wires to the truck contacts and then to the springs for the wipers inside the coal/water bunker.

Fortunately, the plungers on his front truck were working so the loco is now usable. Access to the front truck is not so obvious. It looks as if you can remove the front of the smokebox, unscrew the smoke unit holder and slide it forward, and then the screw will be accessible through the stack hole.
Anyone know how to do this?