Atlas Model Railroad Co. Product Review

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This review was taken from the January 2000 issue of Railroad Model Craftsman and is reproduced with permission of Carstens Publications, Inc.

EMD SD50 diesel locomotive: N Scale

Review by Ken Goslett

Atlas has broadened their N scale product line with the release of General Motors’ SD50 diesel locomotive. This new shell rides on a praiseworthy drive shared with the company’s SD60 and SD60M models.

The Electro-Motive 50 series product line included both four-axle (GP50) and six0axle (SD%)) locomotives powered by 16 cylinder power-plants. Experiments that lead to the 3,500 h.p. SD50 began in 1879 with four SD40X units for Kansas City Southern. The first regular production SD50 examples, with the full 71’2’ length, appeared in the spring of 1981, again for KCS. Late in 1984, a further improvement occurred when the prime mover output was increased to 3,600 h.p. With that change, the 645 prime mover, in production since 1965, had reached its limit. Subsequent models such as the 3,800 h.p. SD60 employed a larger displacement model 710 engine.

The SD50 were sold to eleven railroads between 1979 and 1987, although in today’s post-merger era, ownership divides into a few large blocks. CSX received units sub-lettered B &O, C&O, Seaboard and Conrail. Union Pacific owns units originally purchased by Missouri Pacific, Rio Grande and Chicago & North Western. Norfolk Southern has examples from N&W, Southern and Conrail heritage. Only the modest fleet of KCS SD50’s remains untouched by merger, as does the large Canadian National stable of cowl-bodied SD50F units in Canada. For a detailed roster of SD50 production, consult the April, 1991, issue of RMC.

From May, 1984, until July, 1987, the SD50 was offered concurrently with its successor, the 3,800 h.p. SD60. General Motors built both models on the same frame platform and so similar were the identical length bodies, that differences could be spotted only by the most trained eye.

To quote from The Contemporary Diesel Spotter’s Guide, "Four latched doors in six door panels beneath the radiator grilles differentiate the SD50 from the SD60, which has six latched doors in eight door panels."

The only discernible difference in the two locomotive models was the number and latch arrangement of the rearmost hood doors.

One might be forgiven then for assuming that Atlas, which had produced an N scale model of the SD60 in 1998, would merely paint the existing shell as an SD50. After all, the door area in question measures 7/8" long by 3/8" high and the latches are miniscule. Who would notice?

Happily, the assumption would be wrong. Atlas has produced an entirely new N scale SD50 shell with the prototypically correct door and latch arrangement. Wow! Using the classification system created by diesel fans, the new shell is a "Phase II" SD50 with a frame edge of constant thickness along its entire length and an angled blower duct. As such, it is a wise choice representing almost all SD50 production with the exception of the first 20 units (six N&W and 14 KCS).

Atlas has chosen to decorate the models in accurate prototype paint schemes. Chessie System, Missouri Pacific, Rio Grande and Seaboard System are offered. These will delight modelers keen on the decade of the 1980’s.

Our sample, beautifully decorated in the Seaboard gray, struck a particular chord with this reviewer. A trio of Seaboard SD50’s demonstrated in Cabana, eventually won a significant order from Canadian National. On a memorable winter afternoon, the reviewer and a CN exceutive, cameras in hand, intercepted the Seaboard units as they raced eastward from Toronto. The day might have yielded some excellent photos had the chase van not backed into the ditch while reversing in pursuit.

Silver side window frames and yellow painted step edges highlight the opaque, yet thin, factory paint job. Two numbers plus an unnumbered version are available in each roadname.

Weighing 3.6 ounces, the models’ flywheel drive system is shared with the SD60/SD60M and delivers the same silky smooth performance. The SD50’s slow speed of six scale m.p.h. matched that of the SD60 reviewed in the February, 1999, issue of RMC. At top speed the SD50 was slightly faster at 250 s.m.p.h. at 12 volts. In practical terms however, the difference disappeared during multiple-unit operation of the two models. They ran smoothly together without any surging or bucking.

An internal PC board gives directional lighting. Decoder installation is facilitated by an instruction sheet intended for Lenz system users.

The SD50 is another fine model in Atlas’ series of N scale modern prototype locomotives. A perfect match for the SD60, it will remind us of the days when railroad mergers were regional and not national affairs.