This installation is for the older N Scale Life-Like GP18's using the TCS CN Decoder performed by Tim Diez
The installation is not as difficult as one would think. It requires some trimming of the weights and simple soldering. I simply removed the weights and filed them down in a vice by hand. To avoid short circuits, apply electrical tape to the top of the weights.
The picture below shows the rear weight after filing. These models are light, so only remove enough to fit the decoders.
Next, clip the rear power connection and wire them to the rear decoder half. Be sure to leave enough room to get the weight back in.
Clip the front power connection next, and the motor wires. Wire them to the front decoder half.
Finally, wire the two decoder halves together. Once testing is done and things work correctly, tape the wires in place.