DFH2 The DFH2 was originally designed by
Sifang locomotive works in 1966 as a passenger locomotive of rated power . The design did not enter mass production. In 1973, the design was changed at
Ziyang locomotive works to a power locomotive with a top speed of . The mass was and the starting tractive effort was . The locomotive used a 12V180ZL engine and SF2010 transmission. In 1976, CRRC Sifang produced several
DFH and DFH2 locomotives for use on the Chinese funded Tanzania-Zambia Railway (
TAZARA Railway), becoming the first locomotive to be exported from China.
DFH5 To compensate to the growing needs of growing railway traffic for industrial and mining operations, the Ziyang Diesel Locomotive Factory redesigned the DFH2, addressing technical issues in the manufacturing process and operations, to create the DFH5. The locomotive's pushing capacity was increased to 3300 tons. Between 1975 and 1993, 450 units were manufactured. Early models of the DFH2 and DFH5 locomotives suffered from high oil temperatures in warm environments. To address this issue, in August 1976, the Ziyang Diesel Locomotive Factory improved the lubrication oil pipeline on the DFH5 locomotive No. 0001 to reduce oil temperatures, a change that was further implemented on later units of the DFH5. In 1986, the Ziyang Diesel Locomotive Factory then made improvements to the torque converter in the hydraulic transmission box, adding a new turning mechanism and module axle gears. Improvements were also made to the axle gearbox and
bogie frame. To meet the high-temperature and corrosion-resistant requirements of metallurgical and chemical systems, the locomotive uses fire-resistant, heat-insulating, and corrosion-resistant materials, enabling it to operate in external temperatures of 50°C. These improvements led to the widespread use of the DFH5 diesel locomotive in local railways and industrial and mining enterprises. The DFH5 engine was a 12V180ZJ and transmission ZJ2011, producing of tractive effort with a mass of and with a top speed of . A higher speed was available with a limit of and tractive effort reduced to approximately half. Variants, the
DFH5B and
DFH5C, were introduced in 1985, with modifications to improve reliability and performance – in both where the rated power was increased to , and the mass by . DFH5C was produced for operations in metalworks. One example was produced for shunting in the Chinese port of
Huangpu District, Shanghai.
DFH7 Four units were produced for shunting in mines and industrial environments. ==Metre gauge==