Diesel locomotives were developed in the 1920s. They began to increase in popularity in the 30s as "switchers" in rail yards and factories. Cities encouraged their use to reduce the pollution emitted by steam switchers. The modern version of the diesel locomotive emerged following World War II. Operating cost reductions drove rapid growth until they forced the last steam engines out of service in the early 1960s. There are several types of diesel locomotive:- The diesel-mechanical operates using internal combustion, much like a diesel truck engine. They have very low power and most in use today are switchers.- The diesel-electric uses diesel motors to drive generators that produce electricity to power traction motors. Almost all locomotives that you see in operation today are diesel-electric. The Virginia Transportation Museum has both types of diesel locomotives on display. The railway lines found that a reduction in the size of the crew was a particularly attractive benefit of diesel versus steam. There was no fire, of course, eliminating the need for a fireman. Fueling stops were much less frequent and crews could travel further. However, they did not realize the benefits right away. The powerful railroad unions fought the elimination of the fireman. They also fought the extension of the 100 mile track regions to the 200 or 300 miles that the railways wanted. It took years to win the changes. Today, the diesels typically have two people in each cab, primarily for safety reasons. There was also resistance to the diesel evolution from the steam locomotive engineers and the craftsmen that built and maintained the engines. The railway culture was changing and the impact was being felt by the workers and in the communities that supported the steam locomotives. Would you like to be the engineer of a diesel locomotive? Then come inside the Museum climb aboard our Norfolk Southern SD-40 Locomotive Cab: the actual cab of diesel locomotive #1594.