In order to meet the stricter diesel locomotive emissions standards imposed by the EPA Tier II regulations, EMD modified the SD70MAC and created the SD70ACe. The SD70ACe is powered by a 16 cylinder, 710G3C-12 diesel engine, producing 4,300 horsepower.

     The engine drives an alternator producing AC current that is rectified to DC current and then “chopped” back into AC to power the traction motors. The engine and electrical system are similar to the SD709MAC, but updated with newer technology. Much of the external design is based on the SD90 series locomotives. Some of these features include the full height nose door and rectangular windshields, the large flared radiators with two fans, and the positioning of the dynamic brake equipment at the rear of the long hood. In addition, the inverters were moved from inside the long hood to a box on the walkway behind the cab. Four demonstrator locomotives were built in 2003, followed by 20 pre-production units for CSX in 2004.

      Full production started in 2005 and through 2009, 820 SD70ACe’s have been built for the US and Mexico. Nine more were exported to Venezuela and 46 built for BHP Billton’s iron ore operation in Pilbara, Australia. In addition 10 units from BNSF’s 2008 order were diverted to BHP. Union Pacific painted six units in paint schemes commemorating the six railroads that were merged into UP in the 1980s and 1990s and renumbered them for the year of the mergers.

     These HO scale Athearn Genesis models are factory finished and lettered according to the protoype. The two UP SD70ACe variations currently being offered are factory painted, with the Union Pacific winged shield, the waving American flag on the both sides of the long hood, and differ only in the color of the sill stripe (one is red, the other is yellow).

     These plastic models will have DCC/DC Tsunami Sound decoders or DCC Ready. All models are produced under licensing agreement with Electro-Motive Diesel, Inc.. This ensures the authenticity you expect as an informed collector, and allows us to introduce models of the world's most impressive locomotives while the originials are still new on the rails.