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This review is from Model Railroad News, October 2003. Reprinted with permission of Lamplight Publishing Co.


by David Otte

Referred to as the granddaddy of the road switcher, the American Locomotive Company’s 1,000 horsepower all-purpose locomotive made a lasting impact on the way railroads utilized the diesel electric. No longer just a switcher, the RS-1 proved successfully to railroad men that the diesel could be used efficiently in many roles and in turn set in motion the eventual demise of the steam locomotive in America. Now, for the first time mass produced in O gauge, Atlas O is presenting this historic locomotive as a ready-to-run model for both 3-rail and 2-rail layouts. Modelers can operate their tinplate versions with TrainMaster Command Control and enjoy the realistic sounds of RailSounds while scale modelers can utilize the same set up with the aid of a power inverter (sold separately) or choose a DCC ready version.

Granddad Road Switcher

Mr. John Farrington, President of the Rock Island Railroad has been given the credit for the birth of the RS-1. During the late summer of 1940, Farrington approached Alco with an idea for a locomotive that could be used for both road and switching service. There would be great cost savings for railroads if a locomotive manufacturer could bring to market a machine that could be on the road during the day for example and used as a switcher at night. This means that one locomotive could be available for duty almost 100% of the time, a very economical investment. Alco immediately rose to the challenge put before them by their long time steam locomotive customer and began to build two 1,000 horsepower units for the Rock Island. The manufacturer referred to this model as a specification number E-1640, but by the 1950s its more common name, RS-1, had become prominent in the railroad industry.

There were two very important components to the creation of the RS-1, and they were the 539 engine and the American Association of Railroads B type truck. The low profile 539 prime mover was designed by Alco to directly compete with the Electro Motive Corporations SW and NW switchers. This resulted in what was later called the S1 and S2 Alco switchers. Each model was equipped with a 660 horsepower or 1,000 horsepower turbo charged engine respectively. Production of these units had just begun to take off when the Rock Island put in its request for a new type of locomotive. Alco began with the 1,000 horsepower S2, lengthened its frame by eight feet six inches, added a short hood behind the cab to house a steam generator for use in passenger service, hung an 800 gallon fuel tank and battery boxes under the extended frame, and placed the engine on a pair of road trucks. The choice Alco made for this last design feature proved to be the dealmaker for the road switcher. The AAR type B truck was not a new design and had been used on several locomotives preciously, such as Baltimore & Ohio’s #50 Box cab diesel. The swing bolster, drop equalizer trucks were built by General Steel Castings based on a variation of a Commonwealth design. It has been said by many a railroad crew that no other road switcher ever rode better!

Apparently, Alco knew what it was doing, as this combination of design elements formed a successful product line for this manufacturer and the impetus for the other locomotive companies to further develop the general purpose locomotive. Between 1941 and 1960, 623 RS-1s were built, including the 6-axle truck version (RSD1) constructed for the US Army during World II. It would be another six years before Fairbanks Morse’s H15-44 and EMD’s GP7 would be introduced into road switcher service. Alco later offered up-rated models of the RS-1 in the form of the RS2 and RS3, which had slightly modified car bodies. The RS-1 was used by many US and even Mexican railroads (not to mention service in Iran during the war years) too numerous to mention here, so I will refer the reader to issue #58 of  Extra 2200 South for a complete model roster of the 1,000  horsepower Alco engine. Generally, the RS-1 had a long service life, especially with second and third hand owners, and some are still serving faithfully yet today. In particular, the Arkansas & Missouri #22 comes to mind. Built in April 1943, it was still being used to pull the company’s passenger excursion train until being recently donated – in operating condition – to Museum of Transport in St. Louis. You can check it out on the web at

The 1:48 Scale RS-1

The Atlas O RS-1 is definitely what you would call a workhorse for any layout. Like the prototype, it is well constructed and can handle the everyday operations of a tinplate layout. That is the first impression I got from this model as I removed it from the foam-incased box. It is a hefty chunk of machinery and weighs in at about five pounds. Most of this weight is due to the manufacturer’s emphasis on using die cast metal for every major component except the hoods and cab. The frame, fuel tank, side frames, gearboxes, pilots, and couplers are all made of metal. Furthermore, the sill mounted hand rails are made up of stamped metal stanchions and metal railing. Even the separately applied hand grabs, which number 22 in all, are made of metal.

I immediately become appreciative of this construction as I handled the locomotive, removed its hoods and fuel tank to see the internal workings, and reassembled all the pieces. This use of metal parts allowed me to successfully examine, poke, and prod the model without damaging any of the nice details. All too often, manufacturers load up models with delicate plastic details only to have modelers complain that they are too fragile for operation. This is definitely not the case with the RS-1 and this initial construction feature really scored points with me.

However, the use of metal parts does not put this engine in a tinplate category along with post war era Lionel steamers and diesels. The RS-1 is a full-scale model loaded with crisp details. I checked its general dimensions, including the overall length over the pilots, wheelbase, hood height, truck wheelbase, and cab width with published drawings of the Alco unit and found them to be accurate to within one scale inch.

Besides the size comparison, Atlas O had detailed their RS-1 to match a specific phase of the production model. Generally, most diesels locomotive have changes both internally and externally made to their design by the manufacturer after they have gone into production, and railfans came up with a way to designate these variations. In the case of the RS-1, there are three phases which changed the appearance of the locomotive:  Phase I built between 1941 and 1942 included 13 locomotives with square belly fuel tanks and 36 vertical slats in the radiator shutters; the 395 Phase II units built from 1943 to 1957 had an oval fuel tank and 17 wider vertical slats in the radiator shutters; and a Phase III model offered from 1957 to 1960 had a simplified sheet metal hood construction giving the last 15 units built a noticeable lip to appear on the end of the hoods.

Atlas O wisely chose the numerously built Phase II model for their prototype and followed it very closely. In fact, I was able to determine that the prototype the manufacturer based this model on was built in 1948 or before, as Alco began using welded hood door hinges in January 1949 and the O scale model displays riveted or bolted on hood door hinges. In line with this detail, Atlas has also given their model a rounded end fuel tank vent pipe, visible on the left side of the long hood – an item that Alco changed in 1950 to a squared off end pipe. Along with these little details, Atlas O also got the more identifiable Phase II changes such as the 17 vertical slats of the radiator shutters correct as well. Of course, getting details right isn’t new for this New Jersey manufacturer. Having reviewed all of their locomotive releases to date, I always make the assumption that they will strive to get the details right!

Now, that is not to say they don’t make mistakes. From time to time I have disagreed with their interpretation of a detail or two and the RS-1 is not excluded. Looking at the top of the long hood just in front of the cab, a small rectangular shaped hatch is located here. No one in the real world knew exactly what Alco designed this hatch for, but it appears in most photos available to me as being oval in shape. Perhaps the researchers at Atlas O have proof that shows otherwise, so I will just note this as a questionable observation.

Other attributes of this model include see-through pilot steps, raised walkway tread pattern, separately applied air horn and brake wheels, see-through metal walkway over radiator fan grille, air hoses, widow glazing with add-on windshield wipers, and two unique hand painted crew figures. The modeler will realize that these figures are facing in the long hood direction, which is proper as Alco meant the RS-1 to be operated with the long hood forward. One other notable feature of this model is the AAR B style trucks. They are beautifully rendered with brake cylinders, piping, sanding lines, and metal springs installed separately along with the handbrake chains on the front trucks. In my opinion, they have to be the best AAR B trucks modeled so far in O scale!

Going hand in hand with accuracy and detail is quality of decoration. Atlas O succeeded in this area as well. Our sample came decorated for the New York Central’s class DRS-1a No. 8103. This was one of 5 units delivered to the NYC in early 1948 along with a total of 9 more delivered later in 1948 and in 1950. No. 8103 was renumbered under the PennCentral merger to 9903 and was later retired in April 1972. The NYC RS-1s were delivered in the Lightening Stripe scheme with black and white safety stripes on the pilots. The finish on the O scale model is impeccable, and I was particularly impressed with the neat application of the stripes on the pilots not to mention the gray and white lightening bolts on the hood sides. The model also includes fully readable miniature Alco builder’s plates on the cab sides.


Okay, so this looks to be a great scale model of the RS-1, but how does it run you ask? Very well. As was started with their release of the SD35, the Atlas O road switcher is equipped with TrainMaster Command Control and RailSounds. This is a proven operating system in all respects. There were no surprises with the RS-1 as all the popular commands including: air horn, bell, squealing brakes, CrewTalk, TowerCom, and front and rear ElectroCouplers. Some of the other capabilities of TMCC that came in handy were the abilities to increase or decrease the volume of RailSounds, turn on/off the smoke unit and give it a boost for super smoking action, setting the desired momentum, and finally a “boost” command which provided the locomotive with a little extra oomph to get up a steep grade. In addition to TMCC, the RS-1 has bright, directionally controlled headlights, illuminated number boards, and a powerful smoke unit which produces voluminous amounts of smoke – quite proper for a true Alco diesel locomotive as they were referred to as honorary steam engines by their crews. Of special mention, is that under TMCC the locomotive always starts moving with the long hood in the forward direction just like the prototype was designed to operate.

Two can motors, both with flywheels, propel the Atlas O RS-1 providing all wheel drive. While the manufacturer specifies a minimum operating curve size of O36, I was able to negotiate our sample through O31 curve. It ran smoothly around the tighter radius track sections, but the engine overhangs the track enough that I would still recommend the larger size curved track. Overall the locomotive was a good runner right out of the box with a low consistent speed typical of AC powered equipment – about 12 scale miles per hour. A longer break in period may produce better results however. Between the weight, the power from two motors, and the four traction tires, this O scale road switcher is a great hauler and I had it pulling a consist of 27 recent-make scale-sized freight cars on a level track layout.

If you do not have a TMCC setup, do not feel neglected though. The RS-1 will also operate with a conventional transformer. I tested the engine with out MTH Z4000 transformer and found the Atlas O locomotive to be fully responsive to this power source as well. There are a few things to take note of when running in this mode. First, the modeler will want to install the included 9-volt alkaline battery for uninterrupted RailSounds. The battery connection is smartly located in the real battery box behind the fuel tank. The modeler needs to remove a retaining screw, move the battery box cover forward slightly, then pull the cover out. The 9-volt battery clip lies inside this opening. Secondly, there are a group of manually controlled switches under the cab of the model so that the conventional operator can turn on/off the smoke unit or the sound system. Finally, there is a volume adjustment screw located here as well for getting the sound level just right. If you are using an older AC transformer without a horn/whistle button and bell button, it is suggested that the modeler purchase a Lionel Sound Activation Button for each of these sound effects. A “how to” section in the included owners manual explains the procedure for wiring these buttons to an older style transformer so the exceptional digitally recorded air horn and bell sounds can be enjoyed.

A Truly All Purpose Locomotive

Having the ability to run in command or conventional modes, along with the fact it is only about 14 inches long, the Atlas RS-1 is perfect for almost any size model railroad. It can negotiate tight radius curves and  like the prototype, the Alco model can be used as a yard switcher or over-the-road power. It is a perfect addition to the roster for steam-diesel transition era modelers and even for those modelers concentrating on railroading in the 60s and 70s. On top of this, Atlas O is offering their model in a variety of road names:  Great Northern, Minneapolis & St. Louis, New Haven, Pennsylvania, Santa Fe, Long Island, Rutland, and an undecorated version. Recently, Atlas O announced additional road names to be delivered in October 2003:  Jersey Central, Milwaukee Road, Rock Island, Susquehanna, and Atlantic & East Carolina. No doubt, given time, most modelers will be able to find an RS-1 in their favorite road name making the Atlas O locomotive an even more appealing model to the lager O gauge community.

RS-1 Diesel Locomotive

MSRP:  3-rail: $399.95

2-rail DCC Ready: $349.95

2-rail TMCC:  $399.95

Atlas O, LLC

387 Florence Avenue

Hillside, NJ  07205


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