This installation of TCS Z4X Decoder is for HO Scale Stewart Baldwin DRS 4-4-1000 RS-12 and was performed by TCS
First lift the shell off of the locomotive and you will be presented with the lighting board as shown below.
Next remove the two screws in the top of the lighting board, disconnect the motor tabs, and the track pick-up wires from the the original lighting board and remove it from the locomotive
Mount the A4X decoder where the lighting board was and replace to the screws to hold the decoder in place.
Attach the track pickup wires to the decoder as shown above. Next trim both motor tabs down by about 1/2 inch as you can see in the image above. Attach two wires (one to each motor tab) and connect those wires to the motor tabs on the decoder as shown above.
Install a forward facing LED as shown above. Use your decoder literature to identify the correct pads to use for LED's
Finally, install a rear facing LED as shown above and replace the shell. You are now ready to run!