Atlas Model Railroad Co. Product Review

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This review was taken from the August, 1999 issue of Model Railroad News Magazine and is reproduced with permission of Lamplight Publishing Company, Merlin, OR.

Atlas N scale EMD SD50

Review by David Otte

With the introduction of the SD50 in N scale by Atlas, comes the missing link in the modern EMD SD (special duty) family. The SD50 was Electro-Motive Division’s interim model which was the essential design step from the very reliable, but dated SD40-2, to the higher horsepower, state-of-the-art, six-axle SD60 locomotive.

SD50 evolution

The development of the SD50 can be traced back to the failures of EMD’s SD45. The competition among locomotive manufacturers was hot in the 1960’s for the development of a second generation, high horsepower locomotive when EMD unveiled their 3,600 horsepower, 20 cylinder SD45. Although initial sales were strong, locomotive crews soon discovered what a maintenance headache the SD45’s 20 cylinder 645 engine really was, not to mention it was a real gas guzzler.

EMD soon turned their attention to up-rating the 16 cylinder version of the 645 engine to performance levels approaching that of the SD45’s 20 cylinder engine. This new Fversion of the 645 engine achieved 3,500 horsepower, while being more fuel efficient than the 20 cylinder model. In the fall of 1979, EMD built four, six-axle test units around the new prime mover. Designating the units SD40X, they used a standard length SD40-2 frame, but a longer car body filled the entire frame length, allowing the dynamic brake to be located immediately behind the cab. The success of these units, along with some improvements and modifications, led to the first production of the SD50s in the spring of 1981. The first locomotives were delivered to Kansas City Southern and were now 30" longer than their pre-production brothers.

Although production of the SD50 continued through 1987, it was not a very big seller. The big class one roads such as Burlington Northern, Santa Fe, Southern Pacific, and CP Rail shield away from the SD50 sighting poor economic conditions, as well as doubts about the reliability of the 645 series engine when being pushed to extreme limits. Instead, they continued to order the tried and proven SD40-2. The railroads that did decide to purchase the new six-axle monsters included: Kansas City Southern—10 units; Seaboard System; Chesapeake & Ohio, and Baltimore & Ohio (all members of the new CSX family of railroads) —124 units; Conrail —135 units; Missouri Pacific—60 units; Chicago & North Western—35 units; Rio Grande—17 units; and Canadian National— acquired 60 SD50F units with full-width car bodies.

The SD50 featured a Super Series electronic control system for monitoring of major electrical equipment. Sensing traction conditions, it provided automatic adjustment allowing the SD50 to achieve maximum adhesion on the rails. As a result of this system, three SD50s could handle the work where four older SD40-2s would have been necessary in similar situations. The SD50 also boasted reduced fuel consumption, an engine exhaust silencer, and high efficiency electric cooling fans that operated only when the engine cooling water was hot.

There is no mistaking the SD50 for the older SD40-2. The longer hood of the SD50, as well as the absence of the dynamic brake blister are sure telling signs. But this is not necessarily the case when comparing it to the newer and more successful SD60. With both units measuring 67’ across their pilots, the late phase SD50 is almost indistinguishable from the early production SD60. The easiest spotting feature are the service doors under the radiator air intakes. The SD50 has six doors on each side of the car body while the SD60 has eight service doors. Inside these locomotives is a different story though. The SD60 sports the newer and more reliable microprocessor controlled, 710 prime mover, which is rated at 3,800 h.p. and boasts a 16% increase in fuel economy over the SD50.

Atlas’ missing link

Atlas is offering their model in a non-decoder equipped version, with a PC board that can be replaced by a DCC decoder-equipped board, and a version with a factory-installed Lenz DCC decoder-equipped board. The SD50s are being lettered for the following road names: Chessie System in yellow, blue and vermillion; Missouri Pacific in yellow and gray; Rio Grande in black and orange; and Seaboard System in gray and yellow.

Each road name is available in two different road numbers for both non-decoder equipped and decoder-equipped. Unnumbered versions are also available in non-decoder equipped units in all road names. Furthermore, an undecorated model is available without a DCC decoder. Standard features include: directional lighting, blackened wheels, and a dual brass flywheel equipped, five pole, skewed armature motor housed in an all metal frame.

The Atlas model appears to be an early phase II SD50. It has the larger angular blower housing design located on the fireman’s side and a smaller turbo/exhaust silencer hatch on the roof indicative of units built after January, 1983, while still maintaining the rounded anti-climber and the single pair of vent openings located on the panels just below and to the front of the cab of early production units. The plastic injected-molded shells also features the accurate number of access doors under the radiator intakes for the SD50. The model rides on the correct HT-C style trucks. All dimensions of this 5-1/4" long (over end platforms) model compare well with prototype drawings.

The level of detail on this model is outstanding! All the features of full size locomotives are present down to the hand grabs on the blower housing and on the access panel on the low hood. Even the lifting rings on the roof are represented! I was equally impressed with the delicate yet sturdy handrails and the overall crispness of molded on body details. The horn, brake wheel, and plow are separately applied parts, with the later a greatly appreciated extra on an N scale model.

The couplers are body mounted. The Rapido style coupler included with the model can be easily replaced with Micro-Trains #1015/1016 couplers for a more scale like appearance. My only complaints: the same as we found in our review of Atlas’s SD60 model (MRN November, 1998) the blower housing does not extend out to the edge of the walkway. And since Atlas went as far as to include a plow, how about a bell under the frame?

Our sample came decorated for an unnumbered Seaboard System unit. Seaboard was the second railroad to purchase the SD50 beginning with 25 units in January, 1983, and were assigned to coal trains. Additional purchases were made in the following years with a number of units delivered in Chessie System paint and sub-lettered for CSX family members C&O and B&O. One notable difference in the appearance of the Seaboard units is the location of the headlight which is mounted on the low hood rather than above the cab as on the Atlas model.

Overall paint quality and accuracy was what you would except from Atlas—exceptional. The paint was applied evenly over the entire body with no signs of build-up around details or paint runs. Although our sample had no numbering applied, the lettering and striping that had been applied were crisp and opaque. Here gain, I was impressed with Atlas’ efforts. They prototypically ended the yellow frame stripe just before it reached the front edge of the frame, and applied yellow trip to the step edges. Atlas did a good job matching the Seaboard lettering style as well. They even applied the black and white safety striping on the pilot ends. The only thing left for the Seaboard modeler to do (besides moving the headlight location and adding a bell) is to paint the handrails located at the steps yellow and the jack pads black.

Placing the Atlas model on the test track yielded the same results as our SD60 samples did—another excellent running locomotive! Slow running speeds were very good and the unit runs very quietly. All twelve wheels are powered and insure that the SD50 will have no trouble pulling those long consists of loaded hoppers coming from the local coal mines. Also, all twelve wheels serve as electrical pickups.

We had no trouble with engine stalls while traveling slowly through switches or over rail joints. The SD50 has no trouble negotiating 9-3/4" radius curved track and standard switches, but the length of the locomotive would suggest that using a larger radius would be more visually appealing. The directional lighting functioned well and was visible even at the lowest operating voltage settings.

Once again, Atlas proves itself the master when it comes to manufacturing modern N scale locomotives! Like the SD60 and SD60M, the SD50 will definitely fit into your roster if you are looking for high quality, modern motive power. One thing is for sure, the Atlas SD series in N scale is an outstanding group of models, both in appearance and operation, and is sure to be seen on model train layouts for a long time.