Diesel locomotive Therefore, diesel traction became economical for shunting before it became economical for hauling trains. The construction of diesel shunters began in 1920 in France, in 1925 in Denmark, in 1926 in the Netherlands, and in 1927 in Germany. After few years of testing, hundreds of units were produced within a decade. Diesel-powered or "oil-engined" railcars, generally diesel–mechanical, were developed by various European manufacturers in the 1930s, e.g. by William Beardmore and Company for the Canadian National Railways (the Beardmore Tornado engine was subsequently used in the R101 airship). Some of those series for regional traffic were begun with gasoline motors
Electro-diesel locomotive have exhaust restrictions. Once out of the tunnels, the engines are started and operation is as a normal diesel locomotive. With modern electronics, it is much easier to construct (or adapt) an electro-diesel locomotive or multiple-unit which is equally at home running at high speeds both "under the wires" and under diesel power (e.g. SNCF Class B 82500, Bombardier ALP-45DP). These will normally operate under pure electric traction where possible, and use the diesel engines to extend the journeys along non-electrified sections which would not be cost effective to electrify. They may also be used on long cross-country routes to