What are the speeds of diesel and electric locomotive engines?

Diesel locomotive engines are classified as diesel-mechanical (DM), diesel-electric (DE) and diesel-hydraulic (DH) engines. DM engines run at an average speed of 60 kmph, while DE engines travel at an average speed of 80 kmph, also the average speed of an electric engine. The DH engines are heavy duty ones and maintain an average speed of 120 kmph.