This was Atlas's second attempt at a yard switcher (after their 2003 VO-1000 model). And the good news is that, unlike that earlier effort, this one turned out to be an exceptionally fine loco - both in terms of looks and performance.
These are available with the three different styles of long hood that were common to the MP15DC throughout its production: standard hood, hood with square air filter box and hood with angled air filter box (the air filter box is located in the area immediately ahead of the cab). In addition, various styles of exhaust stacks, sand boxes and pilots are available (varying by prototype).
The mechanism sports all the features one normally associates with "modern" Atlas diesels - IE, split-frame / all-metal chassis, dual flywheels, low-friction drive, all-wheel drive and pickup (no traction tires), blackened / low-profile wheels, directional "golden white" LED lighting, shell-mounted Accumate couplers, all-plastic gearing, etc. The chassis is fully DCC-Ready (and, in fact, available with a factory-installed decoder).
The motor is different from the 5-pole / "scale-speed" motors normally found in Atlas diesels (this one being a closed-sided 3-poler). I assume the reason they went with the smaller motor is that the normal 5-poler simply wouldn't fit. In any case, these MP15's seem to match the speed spectrum of diesels equipped with the larger motor.
Performance on these models is outstanding - smooth, quiet, flawless pickup and throttle response, decent pulling power, etc. My only minor complaint is that at least some of these tend to sound a bit buzzy and toyish (particularly at slow speeds). I guess the reason for this is that three-pole motor. But, whatever. It's a minor quibble at best (and most of them don't exhibit the problem at all).
Trivia - Skytop Models makes a replacement hood that converts an Atlas MP15DC into an MP15AC -
Prototype information -
The 1500hp MP15DC was designed by EMD as a replacement model for the successful SW1500 switcher. The longer frame of the MP15DC allowed for increased fuel capacity and the use of Blomberg road trucks; increased sand capacity was also offered as an option. The first MP15DCs were built for Missouri Pacific in February 1974 and a total of 351 units were produced through the end of production in January 1983. The MP15DC is a versatile locomotive that is employed by both large and small railroads across North America in road freight and yard switching duties. It was also purchased by several non-railroad corporations for use in plant switching service.
Shell removal -
Removing the shells on these is a little more difficult than one normally finds with Atlas diesels. The fit is a bit tighter than is typical, so you can't just grab the shell and slide it up and off. However, inserting a couple of toothpicks (or small screwdrivers or whatever) between the shell and the chassis (on either side of the fuel tank) will free things up enough to allow the shell to lift off.