Cotton Belt GP40M-2 7277
This Cotton Belt GP40M-2 is a factory painted Atlas HO scale model with some added detail. Southern Pacific and Cotton Belt GP40M-2 locomotives were rebuilt GP40s. They were a common sight on the SP system in the early 1990s, the era that I model.
The Atlas model is pretty good right out of the box. The paint job is accurate. Most of the major details are correct. It’s an excellent runner. The mechanism is silky smooth and quiet.
Even so there is some room for improvement. Probably the most noticeable change I made was to add working ditch lights. Detail Associates makes the correct ditch lights for a Cotton Belt GP40M-2. I glued 603-sized surface mount LEDs inside the ditch light castings. The LED leads are 36-gauge magnet wire. This wire is small enough and flexible enough to conceal by running it down the back of the ditch light stand and painting it the same color. To my eye this is much better than having unprototypical wires sticking out of the back of the ditch light casting.
I used another 603 LED to light the Details West beacon. The headlights were redone with fiber optics and new 3mm warm white LEDs. The number boards were separated from the front headlight so that they can operate independently.
Before working on the lighting I made some modifications to the shell. The Atlas GP40 is modeled with rear number boards and class lights. Cotton Belt GP40M-2 locomotives had neither. I filled in the rear number boards with styrene and puttied and sanded until the seams were gone. I sanded off the class lights on both ends. Once that was done I airbrushed the ends with SP scarlet. I had to mix the paint carefully to match the factory painted red “wings” on the short hood. I used Microscale decals to restore the markings on both ends.
Other details included a new SP style snowplow, MU hoses, uncoupling levers, brake lines, speed recorder, wheel slip modulators, windshield wipers, sunshades, an air conditioning unit on the roof, a roof mounted antenna and ground plane with conduit, and a rear mounted air horn with piping. The model is equipped with Kadee “scale” couplers. The front coupler is a long shank type to clear the snowplow.
The model is equipped with an ESU LokSound Select DCC sound decoder. The speaker is mounted in a custom enclosure mounted in the back of the locomotive in the radiator area.