Introduced: 1986 (Kato-made version), 2006 (Chinese-made "Atlas Classic" version) and 2016 (Atlas "Master" version)
The original Kato-made RS-11 shares the same basic chassis as the earlier Atlas/Kato RS-3 model. However, the internal components of the two mechanisms are quite different.
Features include a split-frame metal chassis, split-frame metal truck assemblies, all-wheel drive and 6-wheel pick-up (two wheels being equipped with traction tires). The motor is an open-sided 5-poler. All gearing is plastic. Directional lighting is provided by PC boards mounted on either end of the chassis. The couplers are truck-mounted Rapidos (open pilots). Wheels are low-profile and have no problems on Code-55 track. Starting with the second run, the wheels came "blackened" but still included traction tires. Starting with the third run, the traction tires were abandoned.
The RS-11's drivetrain differs rather significantly from the RS-3 in that it lacks an independent worm assembly. Rather, the worms are built right into the motorshafts (RS-3 on top, RS-11 below) -
I guess the theory behind this "innovation" was that removing the four bearing blocks would result in less friction and, consequently, a smoother running locomotive. Unfortunately, some people reported experiencing occasional "jackrabbit" starts with their RS-11's. Now, there are many theories as to why this particular design failed, but whatever the case, it was quickly abandoned by Kato. The next set of Atlas/Kato diesels (RSD-12, RSD-4/5, GP7 and GP9) would use the original RS-3 chassis and internals.
Having said all that, my Kato RS-11 runs every bit as smoothly, quietly and reliably as any of my other Atlas/Kato diesels. Further, I've never had any of those reported jump-start problems. So, who knows? Maybe I just got lucky.
Atlas severed their ties with Kato in the mid-90s and in 2006 re-released this locomotive under their "Atlas Classic" line (redesigned, retooled, Chinese-manufactured remakes of the locomotives they originally contracted Kato to make for them).
The truck spacing on the original Kato-made RS-11's was a bit off (as compared to the prototype) - this due to Atlas's decision to use the same RS-3 chassis for all of their early Kato-made diesels (presumably as a cost-cutting measure). These discrepencies were all fixed in the new Atlas Classic version.
This newest version is DCC-Ready (and is, in fact, available with a factory-installed decoder). Couplers are now shell-mounted Accumates. The mechanism includes flywheels, metal pickup strips, plastic truck assemblies, low-friction axles, skew-wound motor, 8-wheel pickup (IE, no traction tires), blackened wheels, etc. Performance is typical of Atlas's modern diesel models - smooth, quiet and perfect.
Circa 2016, Atlas revised the internals on these models slightly. As pictured below, the hex nuts on the flywheel end of the wormshafts were removed and replaced instead with U-joint connectors -
The other noteworthy change with the 2016 production run was to the decoders (changed from Lenz to NCE). These models are now marketed under Atlas's "Master" line.
Prototype -
The first RS-11s were produced by Alco in early 1956. This locomotive, classified by Alco as model DL-701, was their replacement for the very popular RS-3 road-switcher. Featuring a V-12, 1,800hp 251B diesel engine, the RS-11 was Alco's answer to EMD's very successful GP9. The turbocharged RS-11 accelerated faster, had a higher tractive effort rating and typically used less fuel than the competition. It was also quite versatile and could be found in heavy haul freight as well as passenger service. The largest owner of RS-11's was Norfolk & Western which purchased a total of 99 units (an additional 35 were added to the fleet after the merger with Nickel Plate). Other major purchasers included Northern Pacific, Pennsylvania and Southern Pacific, all of whom placed repeat orders. With approximately 426 units built for the US and Mexico over 8 years of production, the RS-11 was successful for Alco in that it provided ongoing competition for EMD's popular road-switchers. A few examples of this model are still in service today and can be found working for various shortlines in the US.
Shell Removal -
Removing the shell on the Kato version requires a bit of patience and a gentle hand (IE, leave the elbow grease at home). I use a small screwdriver to pry the shell away from the chassis a little bit at a time (starting at one end and working my way around). Eventually it'll slide up and off. The Atlas Classic/Master versions are much simpler - just take hold of the fuel tank with one hand then wiggle the shell up and off.
Trivia - Atlas used these same shells for their RSD-12 models. The only external differences between the two models are the trucks and the fuel tank.
More trivia - Briggs Models (www.briggsmodels.ca) makes a kit that converts an Atlas/China RS-11 into an MLW RS-18 -
Grade: A (all versions)
Kato-version reviewed: 12/86 Model Railroader ("Let me get right to the point: This is a handsome model that runs as smooth as glass. Manufactured in Japan by Kato (the same firm that made the N scale Atlas RS-3 and several other HO locomotives of late), the locomotive features really exquisite detail... Notice the piping behind the screens on the upper grill. How do they do that? Notice also the detail on the truck sideframes. The handrails are delicate but resiliant, and the detail on the hood and walkways (safety tread) is crisp. I checked the dimensions of the model against prototype drawings and, for all practical purposes, they're on the money: the width and height are perfect, as is the truck wheelbase. The overall length is a little short, and the overall wheelbase measures about a foot short. The reason for this is that Kato has used the trucks, mechanism, and frame from their RS-3 on the RS-11. A viewer would need micrometer eyeballs to the notice the discrepency, however... This is a smooth runner... The top speed is excessive... With one traction tire on each truck it should readily pull about 24 free-rolling N scale cars on straight and level track... The wheels are just a little tight when measured against the NMRA standards gauge... Undec, PRR, BN, NYC, L&N, SP, CV, Conrail, N&W. $49")
(Many thanks to Ron Bearden for the "weirdo motor" pictures and information)