Barnstormin’ Demos

Written by: Gary Dolzall

The Electro-Motive GP35 and its big sister, the DD35, comes to Train Simulator in demonstrator colors!

During the “horsepower race” among American diesel builders of the early 1960s, Electro-Motive dispatched a remarkable 15,000-horsepower demonstrator set on a barn-storming tour of the United States. And now, as a Marketplace product from DTM, the flashy red-and-white liveried GP35/DD35 demonstrator set comes to Train Simulator.

As inevitably was the case during much of the twentieth century when the subject was railroad “super power,” the Union Pacific had its hand in the events that lead to creation of Electro-Motive’s 15,000-horsepower GP35 and DD35 locomotive team. Based on a motive power study it conducted in 1962, Union Pacific issued a call for diesel designs that would deliver 15,000 horsepower in three-unit sets (e.g., 5,000 h.p. per unit). The major U. S. locomotive builders – Electro-Motive, General Electric, and Alco – each responded. Alco and GE’s designs were similar in concept: The per-unit horsepower requirement would be achieved with dual diesel powerplants riding in a carbody atop span bolstered trucks forming a B-B+B-B wheel. GE’s model – the U50 – was rated at 5,000 horsepower; Alco’s offering – the C855 – housed a pair of 2,750-horsepower V-16s per unit and thus was rated at 5,500 horses. In either case, three of the giants lashed together would provide the desired 15,000 (or more) horsepower.

Electro-Motive, with the strength of being the market leader and UP’s primary diesel supplier, presented a different idea. It would create a new four-axle “D-type” version of its Flexicoil truck design and place two 2,500-horsepower 567-series V-16 engines in a shared cab-less carbody to create a 5,000-horsepower unit (to be designated the DD35). But rather than lashing together a third DD35, Electro-Motive would satisfy the 15,000-horsepower-per-set requirement with a four-unit lash-up that consisted of two of EMD’s standard 2,500-horsepower GP35s on each end, with a pair of titan DD35s in between.

During 1963-1964, UP would acquire 23 of GE’s U50s (all cab-equipped), a lone cab-booster-cab three-unit set of Alco’s C855, and 27 cab-less EMD DD35s accompanied by 24 EMD GP35s (in 1965, UP would also acquire 15 cab-equipped dual diesel units designated DD35A). But in the mean-time, with dual-diesel plans in hand and a need to test and prove its potent new offering, Electro-Motive constructed a four-unit, 15,000-horsepower GP35/DD35 demonstrator set in August 1963 with the goal of enticing purchases for the big diesels from other major U. S. railroads.

Electro-Motive’s barn-storming demonstrator set consisted of twin GP35s (EMD road number 5652 and 5654) book-ending a pair of cab-less DD35s (road numbers 5653 and 5655), All were painted in a bright red and white livery. Frequently accompanying the GP35/DD35 demonstrator set was EMD’s “test car” ET-909, which was an EMD F-series “B” unit carbody loaded with testing equipment.

The Electro-Motive GP35/DD35 demonstrator team is known to have operated on at least seven railroads, including the Union Pacific, Missouri Pacific, Kansas City Southern, Burlington Route (CB&Q), New York Central, Pennsylvania, and Frisco (and by the way, if the flashy demonstrator scheme looks quite familiar, it is because the Frisco adopted a very similar scheme for all its locomotives in 1965!). In addition, it is known that the GP35 demonstrators, without their massive eight-axle sisters, demonstrated on the Erie-Lackawanna and New Haven.

As it turned out, the 15,000-horsepower locomotive set exceeded the motive power appetite of other roads and beyond Union Pacific, only Southern Pacific purchased the DD35 (with an order for three units). The GP35 was, on the other hand, an unbridled success and between 1963 and 1966, 40 railroads purchased more than 1,300 GP35s. As for the EMD 15,000-horsepower GP35/DD35 demonstrator set, when its barn-storming and testing tour was done, the four units joined the Union Pacific roster.

Now, thanks to Partner Programme member DTM, the GP35 and DD35 in demonstrator colors are available as a Marketplace release entitled “DD35 Demonstrator Add-On” (which for use also requires the previously released Union Pacific DD35 Add-On). Naturally, the burly demonstrators will be perfectly suited for duty on Train Simulator’s Union Pacific Sherman Hill route, but given their history of working on a variety of railroads, they’ll be right at home on virtually any American Train Simulator route. Just like DTM’s popular Union Pacific GP35 and DD35s, these new demonstrator locomotives are magnificently re-created with exacting attention to detail and operational authenticity. And as an added bonus, the pack even includes the unique test car E-909.

Ready for some high-horsepower railroad barnstorming’? The remarkable GP35/DD35 demonstrators are available now at the Dovetail Games and Steam Stores! – Gary Dolzall

The 15,000-horsepower Electro-Motive demonstrator set of August 1963 consisted of four locomotives, a pair of standard 2,500-horsepower GP35s such as No. 5652 (above), and a duo of dual-powered, eight-axle, 5,000-horsepower DD35s configured in cab-less “booster” form (below). Each of the EMD diesels were dressed out in a brilliant red-and-white livery. Screenshots by Gary Dolzall

Often accompanying the GP35/DD35 demonstrator set was Electro-Motive test car E-909, which was an F-series “B” unit carbody equipped with a range of testing equipment.

It was a request by Union Pacific that caused all three of America’s biggest locomotive builders of the time – Electro-Motive, Alco, and General Electric – to design 15,000-horsepower locomotive sets. Fittingly enough working on the Union Pacific, the GP35/DD35 demonstrators, led by GP35 5652, have a priority piggyback train in tow westbound from Cheyenne, Wyoming (above), then grind their way up the unforgiving east slope of Sherman Hill (below).

In brilliant red and white demonstrator livery, the GP35/DD35 team makes a magnificent site (above and below) as it climbs Sherman Hill near Buford, Wyoming. Following its barn-storming tour, the locomotive set was acquired by Union Pacific.

With test car E-909 splicing the powerful diesel lash-up, the GP35/DD35 demonstrator set swings past snow fences on the east slope of Sherman Hill. DTM’s new Marketplace pack brings the demonstrator GP35, DD35, and test car to Train Simulator.

As seen from trackside and from behind the engineer’s control stand (above and below), GP35 demonstrator 5652 reaches the highest point of the transcontinental railroad at Sherman, Wyoming. While the big DD35 garnered limited interest (UP and Southern Pacific were its only buyers), 40 North American railroads purchased more than 1,300 of the highly successful Electro-Motive GP35.

Pulsing with 15,000 diesel horsepower, the bright-liveried GP35/DD35 demonstrator climbs through Granite, Wyoming. In addition to being a perfect fit for use on the Train Simulator Sherman Hill route, the DTM Marketplace GP35/DD35 demonstrator set will be ideal for use on a variety of American Train Simulator routes – and it’s available now!

Gary Dolzall


  • Looks great! Are we also going to see Southern Pacific GP35s and DD35s in TS as well?

    • No info shared with me on that TheRealSFC, will see what I can find out

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