The EMD DD35 was a 5,000 horsepower (3,700 kW) diesel-electric locomotive of D-D wheel arrangement built by General Motors Electro-Motive Division for the Union Pacific Railroad and Southern Pacific Railroad. In the early 1960s, Union Pacific started asking for a 15,000 hp (11,200 kW) 3-unit locomotive set to not only replace their turbine locomotives, but to bring new generation of diesel locomotives to the states, and then put them into use.