Centennial BY DON R. FLYNN/PHOTOS BY THE AUTHOR


HUNGRY? During the mid-1960s, Union Pacific was very hungry — for horse- power, that is. Freight business had been increasing steadily during the decade and the fast-growing popularity of TOFC (trailer on flat car) piggyback service was adding even more volume. The railroad’s appetite for power capa- ble of maintaining high-speed freight train schedules across the western two- thirds of the nation was in demand. The relatively mild topography to be found in midwest did not require mas- sive amounts of power to maintain the operating speeds desired, but the grades of the western high plains and more notably the seemingly never-end- ing roller coaster mountain and desert terrain of the far West was another matter.


To overcome these challenges, how about a locomotive with two 3300 h.p. engines, an 8000 gallon fuel tank, and both the latest proven technologies and


44 AUGUST 2013 • RAILFAN.COM


promising new features? General Mo- tors’ Electro-Motive Division (EMD) and Union Pacific’s Operating, Engi- neering, Purchasing, Marketing and Public Relations departments essen- tially formed a team to effectively pro- duce and introduce a locomotive model that would not only meet the railroad’s traffic needs but also gain the public’s attention. Capitalizing on their upcom- ing historic event, EMD and Union Pa- cific introduced the DDA40X “Centen- nial” locomotive in 1969, numbered in the 6900-series commemorating the 100th anniversary of the driving of the Golden Spike completing the transcon- tinental railroad [See the May 2013 RAILFAN& RAILROAD for more about the Golden Spike. —Ed.]. UP 6900 was rushed to completion to allow it to be part of the ceremonies that took place in Utah on May 10, 1969.


A heavy advertising campaign from both EMD and UP made the introduc-


tion of the Centennial hard to miss. Weighing in at 545,000 pounds and just less than 100 feet in length, this 32- cylinder, twin engined, 6600 h.p. giant was the biggest and most powerful diesel locomotive ever built at the time. Building off the railroad’s success with the DD35 program, the DDA40X was considered the next step in develop- ment, with “X” denoting an experimen- tal EMD design. As such, many of the developments tested on the Centenni- als would later find their way into reg- ular production EMD diesels. For in- stance, the DDA40X used modular electronic components which would lat- er be introduced in the “Dash-2” series diesels. Though the Centennials sport- ed the “widecab” look (borrowed from EMD’s FP45), it would be many years before this design would become com- mon for American diesels.


The introduction of the Centennials continued a long history developing big


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