This installation is for N ScaleWalthers RS 2 uses TCS K2D4 Decoder and was performed by A.G. and N.G.
The upper picture shows the Walthers RS2 with its shell on.
This picture shows the locomotive's chassis with its shell taken off and the original lighting board. Be careful as you take off the shell because it is difficult to remove and can be broken easily.
Place some Kapton tape on the top of the chassis as shown in the picture above.
Place some Kapton tape undearneath of the decoder's LED ( circled in red ) to prevent any shorts.
This is a picture of the fully installed board. All in all it is not a very difficult installation. If you, for any reason, need to remove the K2D4, it will have a tendency to get hung up on the front LED, so you will have to lift this LED over the hump in the locomotive frame.