EMD DDA40X

The EMD DDA40X was a 6,600 hp (4.92 MW) D-D diesel-electric locomotive built by the General Motors EMD division of La Grange, Illinois for the Union Pacific Railroad. Nicknamed "Centennial" and "Big Jack", it uses two diesel engines (each providing 3,300 hp (2.46 MW)), and although recent locomotive designs such as the AC6000CW, SD90MAC and the China Railway DF8C have come close, the DDA40X remains the most powerful single-unit diesel locomotive type ever built. It is also the longest single-unit diesel locomotive ever built.