An Electro-Motive Division SW1200 end-cab switcher joins the ever-growing lineup of HO scale diesel locomotives from Rapido Trains. The model has an injection-molded plastic body with railroad-specific details; a die-cast metal frame, chassis, and gearboxes; and loads of separate, factory-applied, prototype-specific detail parts.
Electro-Motive Division produced the SW1200 from January 1954 to May 1966. During the course of the production run, 737 diesels were built for railroads in the United States. Another 287 were produced by General Motors Diesel Division for Canadian roads. The switchers, used in heavy industrial, terminal, transfer, and yard work, were equipped with 12-cylinder 567B diesel engines.
Our sample is decorated as Milwaukee Road no. 638, one of 48 class 12E-S SW1200s rostered by the railroad. The first batch of units was built in January 1954 and numbered 1637 to 1642. The remaining diesels, 2020 through 2061 (no. 638 started life as no. 2033), were built in November 1954. All of the 1,200-hp locomotives were renumbered into the 600 series in 1959. Seventeen of the end-cab switchers were renumbered a third time into the 700 series in 1984.
The 638 was sold to A.O. Smith in July 1979. It was repainted and renumbered 200. The unit then went to Min-nesota Commercial (MNNR) in the Twin Cities. The unit retained it’s A.O. Smith road number, but was repainted into the railroad’s red-and-white paint scheme. As of May 2021, the switcher was in storage on the railroad’s property with the stacks capped.
Disposition information in The Milwaukee Road Diesel Power by Frederick Hyde and Dale Sanders (The Milwaukee Road Historical Association, 2009) shows that some of the SW1200s were scrapped, while others went on to serve on Class 1, regional, Some end-cab units were sold to locomotive leasing companies and to industries for use as plant switchers.
The model. The Rapido SW1200 features an illuminated cab interior detailed with a control stand, high and low voltage cabinet, two seats, a brake wheel, and a fire extinguisher. Crew figures aren’t included with the model.
The front and rear pilots are plastic castings attached to the metal chassis with two screws concealed under the draft-gear box. U-shaped etched-brass walkways are attached to the top of the frame; our sample has a raised tread pattern. The steps are see-through etched-metal parts.
The combined handrail and stanchion assemblies, uncoupling levers, m.u. hoses, and trainline hoses are plastic. The standalone handrails and grab irons are factory-installed and painted formed wire parts. The windshield wipers are etched metal. Like other Rapido models, the switcher features plenty of underbody conduit and piping.
Additional factory-installed parts include a cab vent on the roof, a deck-mounted m.u. receptacle on each end, a single-chime air horn on the front of the cab, and a bell on the hood. Our sample also included a package with two each of the following modeler-installed parts: all-weather windows with glazing, smokestacks, cab sunshades, and brackets.
Railroad-specific parts on the Milwaukee Road SW1200 include “trash can” spark arrestors, cooling coils in front of the air reservoirs, Type A solid-bearing trucks, and twin-beam headlights. The headlights are directional. The model also has working ground lights below the cab on both sides.
Under the hood
Pages six and seven of the operating manual take you through the steps (with some humor interjected) needed to remove the shell from the chassis. Since we needed the model for photography and video, I decided to rely on the exploded parts diagram to “see” what’s under the hood.
The motor and its dual flywheels are nestled in a cradle centered on the chassis. The printed-circuit board and the ESU LokSound Select sound decoder are mounted on top of the motor. The downward-facing speaker is located above the front truck.
Tale of the tape. The SW1200 tips the scales at 10.5 ounces. The couplers are approximately .020″ high on both ends, but this didn’t pose any issues when pushing and pulling cars. The wheels are in gauge.
I compared Rapido’s model to prototype drawings in the 1956 Locomotive Cyclopedia of American Practice (Simmons-Boardman Publishing). The model closely follows the dimensions shown in the illustrations.
The orange and black paint is smooth and evenly applied, and the lettering placement matches a prototype image of the full-size locomotive I found online. One difference I noticed was the bell and bracket were painted black, not silver, on the prototype.
Our sample is equipped with a dual-mode LokSound sound decoder. When I first put the locomotive on the rails to test it, I struggled getting it to run reliably. It turned out the model was over-lubricated. After wiping off the excess lubricant and giving the wheels a thorough cleaning, the unit ran much better. Rapido president Jason Shron said, “We’re aware of the issue and we’re working to improve that on future releases.”
I first tested the model in direct current (DC) using an Atlas Right Track power pack (per the operating manual, do not use the Atlas 313 Universal power pack with this model). The sounds came on at 8V, which is typical on sound-equipped models in a DC environment. The locomotive ran at 6 scale mph at 10V and topped out at 147 scale mph at 14V. Rapido locomotives can safely operate between 0V and 16V.
Then I tested the end-cab switcher in Digital Command Control using an NCE PowerCab. The model moved at 5 scale mph at step 2. At step 28, the model achieved a top speed of 111 scale mph. The full-size SW1200 had a top speed of 65 mph.
You can adjust the minimum and maximum speeds using CVs 2 and 5, respectively. The LokSound decoder manual can be found under the Product Support tab at Rapido’s website.
The locomotive has a drawbar pull of 3.04 ounces, equivalent to 43 free-rolling freight cars on straight and level track. The SW1200 was able to pull eight 50-foot freight cars up the 3 percent grade on our Milwaukee, Racine & Troy staff layout.
Covering all the bases. I applaud Rapido Trains for offering the HO scale SW1200 with railroad-specific details. A look at the exploded-view diagram reveals that this is definitely not a one-size-fits all model.
With paint schemes covering roads from coast to coast and border to border, there’s sure to be an SW1200 ideal for your model railroad.
Facts & features
Price: Direct current, $225; with
dual-mode sound decoder, $335
500 Alden Rd., Unit 21
Markham, ON, Canada L3R 5H5
Era: 1959 to July 1979 (as decorated)
Road names: Milwaukee Road; Baltimore & Ohio; Burlington Northern; Chicago, Burlington & Quincy; Chicago & North Western; Conrail; Denver & Rio Grande Western; Grand Trunk Western; Great Northern; Missouri Pacific; New York, New Haven & Hartford; Northern Pacific; Penn Central; Pennsylvania RR; Rock Island; Soo Line; and Southern Pacific. Three road numbers per scheme. Some road names have paint scheme variations. Also available undecorated.
Correctly gauged wheels
Illuminated headlights, ground lights, and number boxes
Metal couplers (.020″ high on both ends)
Prototype-specific exhaust stack and battery box door styles
Type A or Flexicoil trucks, as appropriate
Underbody piping and conduit detail
Weight: 10.5 ounces
With or without positionable drop steps, as appropriate