| DFH2, DFH5, DFH6, DFH7, DFH21 东方红2、东方红5、东方红6、东方红7、东方红21 | |||||||||||||||
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 DFH2-0008 | |||||||||||||||
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The China Railways "Dongfang Hong"diesel-hydraulic locomotive classesDFH2,DFH5,DFH6, andDFH7, built from the 1970s to 1990s, were all used asshunters on the Chinese railway network.
The use of diesel-hydraulic shunters has fallen out of favour on the Chinese rail network, withdiesel-electric locomotives being used. However, diesel-hydraulic machines continued to be produced for industrial railways – mainly theChina Railways GK classes.[2]
TheDFH21 class is ameter 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 theVietnam Railways where they are known as theD10H.
The DFH2 was originally designed bySifang locomotive works in 1966 as a passenger locomotive of rated power 1,470 kW (1,970 hp). The design did not enter mass production, but in 1973, the design was changed atZiyang locomotive works to a 650 kW (870 hp) power locomotive with a top speed of 62 km/h (39 mph).[1][img 1]
The mass was 60 t (59.1 long tons; 66.1 short tons) and the starting tractive effort was 192 kN (43,000 lbf). The locomotive used a 12V180ZL engine and SF2010 transmission.[4]
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.[3]
The DFH5 class was produced in large quantities. The engine was a 12V180ZJ and transmission ZJ2011, producing 278 kN (62,000 lbf) of tractive effort with a mass of 86 t (84.6 long tons; 94.8 short tons) and with a top speed of 40 km/h (25 mph). A higher speed was available with a limit of 80 km/h (50 mph) and tractive effort reduced to approximately half.[2][img 2]
Variants, theDFH5B andDFH5C, were introduced in 1985, with modifications to improve reliability and performance – in both where the rated power was increased to 920 kW (1,230 hp), and the mass by 4 t (3.9 long tons; 4.4 short tons). DFH5C was produced for operations in metalworks.[3]
One example was produced for shunting in the Chinese port ofHuangpu District, Shanghai.[1]
Four units were produced for shunting in mines and industrial environments.[1]
Locomotives similar in design to the DFH2 type but built to meter gauge and used as universal locomotives.[1][5] The locomotives were used on theKunming metre gauge railway, including passenger services.[6][img 3]
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 fromKunming North Railway Station to several nearby stations. As of 2014[update], these trains were still in operation.[7]
30 of the locomotives are also used byVietnam Railways, where they are known as theD10H.[8] In 2005, Vietnam railways had 20 units operational.[9] In 2009, ten of the engines hadCaterpillar Inc. 3512B engines fitted as replacements.[10]
DFH2 0008 and DFH5 0001 are both preserved at the BeijingChina Railway Museum.[11]
