Travel westbound on Interstate 94 in North Dakota and one can’t help but notice the vastness of the rolling plains.  The old Northern Pacific (NP) mainline follows a meandering route around the hills while the highway undulates with the terrain.

Very little variation to this wavy landscape is noticed until one reaches Bismarck - the state capital - where the mighty Missouri River cuts through the plains at the bottom of a deep valley.  The highway drops quickly down to the valley floor, while the NP mainline curves through downtown and crosses high above these waters on one of the city's most recognizable structures.  Three enormous trusses provide for the BNSF what they did for the NP and the Burlington Northern: a reliable link between East and West.
Standing below the bridge, the blue waters of the river tremble in the breeze.  The smell of creosote ties emphasized because of the day’s 40-degree (104-degree Fahrenheit) summer’s heat wafts down from the bridge deck high above my head. 

Suddenly, pigeons resting on the trusses above rush off of the structure, flying away just as the sounds of roaring EMD 710 prime movers overcome the sound of crashing waves from a passing boat.  Two big locomotives emerge out of the trees on the opposite bank and move across the steel spans, which date back to 1905.  Their angular noses are intimidating and their mean look accurately represents the sheer power and size of these locomotives.  This pair of SD70ACe locomotives – two ofEMD’s most modern units – is still roaring in notch eight, slowly lifting a heavy unit coal train out of the valley.

As the locomotives pass high above, I can feel their immense sound shake my bones, and their immense power shakes the riverbank below my feet.  These modern AC-traction EMDs are used by the BNSF and other Class I roads on heavy unit trains, including on the many coal trains originating in the Powder River Basin in Wyoming, some of which pass via Bismarck. 

SD70: The Rebound That Saved EMD

In the late 1980s, EMD was struggling.  After the production and commercial failure of their unreliable SD50 locomotive series, EMD’s once-polished reputation was severely tarnished.  Once the dominant locomotive manufacturer in North America, the failure of the SD50 opened the door for rival manufacturer GE Transportation to step in and take over that prestigious number one spot.

EMD, scrambling to regain momentum and their customers’ trust, launched the SD60 series of locomotives. These diesels were purchased by several roads and were much more reliable than their SD50 predecessors. The SD60s helped EMD close the gap between its sales and those of GE.

However, it wasn’t until the early 1990s when EMD released the first of the SD70 series of locomotives that the manufacturer started to regain steam.  The SD70 (and its variant models), developed in response to GE’s new – at the time – Dash-9 series of locomotives, was an immediate hit among North American railroads. 
 

One large reason for their success was the introduction ofEMD’s HTCR radial (steerable) trucks.  Instead of following the rail, the trucks could steer themselves around the curve.  This reduced wear-and-tear on the rails and the locomotive’s wheels, and it slightly increased tractive output around the corner.  This steerable option – which GE does not offer (even today) – is still a significant reason that railroads purchase new EMD 70-series units over their GE competition.  Another important selling point is the new, easily-maintained computer and microprocessor systems on board.