Quick-and-Dirty IHC 4-4-0 and 2-6-0 Decoder Installation

I did an IHC 2-6-0 Mogul for my first decoder install, using a Lenz LE103XF decoder and some tips from Tony's Train Exchange. Short of plugging a decoder into a DCC-ready socket, this is about as easy as it gets. The 4-4-0 is identical, except that it doesn't have as many wheels.

The decoder is mounted in the tender, as the boiler is filled with weights. The IHC motor is already isolated from the frame, making things easier. I did not rewire the headlight to a decoder function output. This means that the light is on as long as the track is powered.

Note that wires solder much more easily if they are pre-tinned.

1. Remove the tender shell. There is a tab at the front of the tender that holds it on.
2. Cover the tender weight with electrical tape. This may not be strictly needed, but won't hurt.
3. Remove the pilot screw (#69 on the exploded diagram - you did keep it, didn't you?) and pilot truck from the locomotive.
4. Remove screw #64, which is underneath the pilot truck and holds the boiler to the frame.
5. Remove screw #78, which is at the back end of the locomotive frame and passes through the drawbar.
6. Lift the boiler and cab from the frame. The front headlight is still connected; be careful not to pull the wires out or strain them more than necessary. Swing the rear of the boiler to the side to access the motor. You may have to pull the handrails from the pilot deck to remove the boiler, or they may already be loose.
7. Remove the motor holder at the back of the motor. Remove the motor from the frame. If the worm gear catches, rotate the drivers to help free it. This is a good time to clean out excess grease from the gears and relubricate if needed.
8. Cut the motor wires where they meet the tabs that protrude from the top of the frame. Note which solder pad on the motor is connected to which tab. (Mine was upper pad = left side.)
9. Solder the motor wires from the decoder to the motor solder pads per the decoder installation instructions, discarding the old wires. (Alternately, you could solder the decoder to the cut ends of the motor wires if you need the extra length.) The NMRA color code is grey wire = left rail motor feed, which is the upper pad on my loco. Solder the orange wire to the other pad.
10. Solder the decoder pickup wires (black and red) to the contact plates in the tender - black to the left rail contact (which is above the rear truck on mine) and red to the right rail contact. Check the tender wheels to see which side is insulated on each truck to make sure.
11. Clip the exposed portions of the remaining decoder wires and cover with heatshrink tubing or electrical tape.
12. Replace the boiler, tucking the motor wires under the cab where they won't rub against any moving parts.
13. Replace the pilot truck. Test for proper operation. (Test after replacing the boiler so that the headlight wires aren't damaged during testing.)
14. Assuming everything works, place the decoder and extra wires in the tender shell and snap it back into place. There is already an opening at the front of the tender shell for the wires.