| DFH2, DFH5, DFH6, DFH7, DFH21 Chinese: 东方红2、东方红5、东方红6、东方红7、东方红21 | |
| Powertype: | Diesel-hydraulic |
| Builder: | DFH2, DFH5, DFH6, DFH7 Ziyang locomotive works DFH2, DFH5, DFH21 Sifang locomotive works |
| Builddate: | DFH2 1973 DFH5 1976-1988 DFH6 1981 DFH7 1988 DFH21 1977 (prototype), 1982 |
| Totalproduction: | DFH2 ? DFH5 >500 DFH6 1 DFH7 4 DFH21 >29 |
| Uicclass: | B'B' |
| Gauge: | DFH21 |
| Minimumcurve: | (?) |
| Length: | DFH2 12.41NaN1 DFH5 13.71NaN1 DFH6 ? DFH7 ? DFH21 121NaN1 |
| Transmission: | Hydraulic |
| Maxspeed: | DFH2 62km/h DFH5 40km/h DFH6 ? DFH7 ? DFH21 50km/h |
| Poweroutput: | DFH2 650kW DFH5 790kW[1] DFH6 1740kW DFH7 790kW DFH21 640kW |
| Operator: | China Railway DFH2, DFH5, DFH6, DFH7, DFH21 Vietnam Railways D10H |
The China Railways "Dongfang Hong" diesel-hydraulic locomotive classes DFH2, DFH5, DFH6, and DFH7, built from the 1970s to 1990s, were all used as shunters on the Chinese railway network.
The use of diesel-hydraulic shunters has fallen out of favour on the Chinese rail network, with diesel-electric locomotives being used. However, diesel-hydraulic machines continued to be produced for industrial railways – mainly the China Railways GK classes.[2]
The DFH21 class is a meter gauge version of the DFH2, and was used on the Yunnan–Vietnam Railway for both passenger and freight services; the same machines are used on the Vietnam Railways where they are known as the D10H.
The DFH2 was originally designed by Sifang locomotive works in 1966 as a passenger locomotive of rated power 1470kW. The design did not enter mass production, but in 1973, the design was changed at Ziyang locomotive works to a 650kW power locomotive with a top speed of 62km/h.[3] [4]
The mass was 60t and the starting tractive effort was 192kN. The locomotive used a 12V180ZL engine and SF2010 transmission.[5]
In comparison to the DFH2 type, a number of changes were made for the DFH5: a twin-speed transmission allowing a higher top speed when running without a heavy load was included, and the mass was increased to improve traction.[1]
The DFH5 class was produced in large quantities. The engine was a 12V180ZJ and transmission ZJ2011, producing 278kN of tractive effort with a mass of 86t and with a top speed of 40km/h. A higher speed was available with a limit of 80km/h and tractive effort reduced to approximately half.[2] [6]
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 920kW, and the mass by 4t. DFH5C was produced for operations in metalworks.[1]
One example was produced for shunting in the Chinese port of Huangpu District, Shanghai.[3]
Four units were produced for shunting in mines and industrial environments.[3]
Locomotives similar in design to the DFH2 type but built to meter gauge and used as universal locomotives.[3] [7] The locomotives were used on the Kunming metre gauge railway, including passenger services.[8] [9]
As of 2012, Kunming rail fans report that DFH21 locomotives are still used to haul a few passenger trains a day along the metre gauge tracks from Kunming North Railway Station to several nearby stations., these trains were still in operation.[10]
30 of the locomotives are also used by Vietnam Railways, where they are known as the D10H.[11] In 2005, Vietnam railways had 20 units operational. In 2009, ten of the engines had Caterpillar Inc. 3512B engines fitted as replacements.[12]
DFH2 0008 and DFH5 0001 are both preserved at the Beijing China Railway Museum.[13]