EMD DDA40X

The DDA40X is a 6600 horsepower (4.9 MW), eight axle diesel locomotive. The locomotives were made specifically for the Union Pacific Railroad. They are also known as Centennial locomotives due to the fact that their initial delivery began on the 100th year anniversary of the driving of the golden spike at Promontory Summit, Utah. Union Pacific numbered the locomotives 6900-6946. Only 47 were made. Measuring 98 feet 5 inches (30 m), they are the longest diesel locomotives ever built. The locomotive frames were manufacted by John Mohr Company . The fuel tank, which weighs 30 tons when full, can carry 8,000 US gallons (30 m³) of diesel fuel. Aside from their huge size, the engines could be identified by an early wide-nose cab and flared radiator grilles similar to those on the SD45 . These radiators raise the roofline more than 17 feet (5 m) above the rails. Of all the double-diesel locomotives used by Union Pacific, only the DDA40X remains. Some were donated to museums; most were scrapped in the 1980s. One of them, no. 6936, was kept by Union Pacific. It powers excursion trains and is sometimes even used for revenue freight service.