Diesel locomotive a locomotive whose wheels are driven by a gearing with an internal combustion engine as the prime power. According to the type of locomotive internal combustion engine, the vast majority of the internal combustion engines used in China's railways are diesel engines. Fuel oil (diesel) is burned in the cylinder to convert thermal energy into mechanical energy output by diesel crankshaft, but it is not used to drive the driving wheel directly. Instead, it is converted into mechanical energy suitable for locomotive traction characteristics through the transmission device, and then drives the locomotive driving wheel to rotate on the track through the running part.

Diesel locomotives are the most widely used. In China, the term diesel locomotive is traditionally used to refer to diesel locomotives. In a diesel locomotive, a transmission device which is as important as the engine and conforms to the traction characteristics is installed between the internal combustion engine and the driving wheel. There are three kinds of driving devices: mechanical driving device, hydraulic driving device and electric driving device. Diesel locomotive with electric drive is called electric drive diesel locomotive, etc.

At the beginning of the 20th century, foreign countries began to explore the trial production of diesel locomotive. In 1924, the Soviet union built an electric locomotive and put it into use on the railways. In the same year, Germany used diesel engine and air compressor to match, using the exhaust heat of diesel engine to heat compressed air instead of steam, and refitted the steam locomotive into an air-driven diesel locomotive. In 1925, the United States put a 220 kW electric drive diesel locomotive into operation, engaged in the shunting operation. In the 1930s, the diesel locomotive entered the trial stage. In the late 1930s, some mainline passenger diesel locomotives with a power of 900 ~ 1,000kw were developed. After the second world war, due to the rapid increase in performance and manufacture technology of diesel engine combustion engine car most equipped with exhaust gas turbo system, power is about 50% higher than that of the war, configuration of dc power transmission and hydraulic transmission device to accelerate the development of internal combustion engine car, in the 1950 s, the internal combustion engine car number of rapid growth. In the 1960s, high-power silicon rectifier was successfully developed and applied in locomotive manufacturing, and the ac-dc electric drive of 2 940 kw diesel locomotive appeared. In the 1970s, the power of single diesel locomotive has reached 4,410kw. With the development of electronic technology, the 1840 kW ac and ac electric drive diesel locomotive was trial-produced by the federal republic of Germany in 1971, thus providing a new way for the technical development of diesel locomotive and electric locomotive. The subsequent development of diesel locomotive has made new progress in improving the reliability, durability and economy of locomotive, preventing pollution and reducing noise.

China began to manufacture diesel locomotives in 1958, and three types of locomotives, such as dongfeng locomotives, were first put into mass production. After 1969, 15 new models such as dongfeng 4 were successively mass-produced. Compared with the first-generation diesel locomotive, the engine's power, structure, thermal efficiency and transmission efficiency were significantly improved. In addition, the functions of resistance braking or hydraulic braking and hydraulic reversing, protection of various locomotive systems, fault diagnosis display and microcomputer control are added. A series of new technologies such as load-bearing vehicle body and hydrostatic drive are adopted. Locomotive reliability and service life, the performance has been greatly improved. The speed of the dongfeng 11 passenger locomotive reaches 160 km/h. At the same time of producing diesel locomotive, China has successively imported different quantities of diesel locomotive from Romania, France, the United States, Germany and other countries.