China Railways DF11

The  DF11 is a semi-high-speed diesel-electric locomotive used on the People's Republic of China's national railway system. This locomotive was built by Qishuyan Locomotive and Rolling Stock Works.

Overview
The China Railways DF11 is a semi-high-speed passenger diesel-electric locomotive. It was an important scientific and technological objective of China's Eighth Five-Year Plan, and was designed for 160 km/h runs on the Guangzhou-Shenzhen Railway. The Guangzhou-Shenzhen Railway opened with an operating speed of 160 km/h, utilizing high-speed passenger trains and the level of potential development of a new type of high speed passenger diesel locomotive.

By the end of 1990 development had begun by the Qishuyan Locomotive Works, who modified a DF9 locomotive, changing traction motor gear transmission ratio, thereby increasing the maximum speed from 140 km/h up to 160 km/h. The new locomotive was then tested to obtain the experimental data for high-speed diesel service.

In 1991, the Ministry of Railways ordered the new locomotive based on the design plans developed by the Qishuyan plant. Code-named the DF11, the first DF11-0001 was completed in December 1992, with the test trials completed in August 1993. The next locomotive, No. 0002, reached the maximum speed of 183 km/h during a test in the National Railway Test Centre (Eastern Suburbs Branch) in April 1994.

After the completion of the trials, the DF11 was formally placed into service on the Guangzhou-Shenzhen High Speed Railway Line in December. Production of the DF11 has stopped production as of 2005, Qishuyan factory produced 459 units total (license number 0001-0458, 1898), with DF11 1898 being named "The Zhou Enlai" (the number is the same as Zhou Enlai's year of birth), belonging to Shanghai Railway Administration Shanghai Locomotive Depot.

The DF11 diesel locomotive is equipped with an AC-DC electric transmission, 16V280ZJA diesel engine, 1 × three-phase AC synchronous alternator model JF204C, and 6 × ZD106 DC traction motors. Maximum braking power from the diesel is 3,610 kW, with nominal wheel power at 3040 kW, capable of sustaining operating speeds of up to 160 km/h. Maximum design speed of the Co-Co trucks is 170 km/h.

The cab design incorporates a 25° inclination for streamlining. The locomotive microcomputer control system consists of constant power excitation control, cooling, anti-wheel slip transfer control, fault diagnosis display, with full power to test the resistance of dynamic braking system functions, and electro-pneumatic braking system. The DF11 can haul a 640 t passenger train (about 12 cars) up to the maximum balancing speed of 167 km/h on straight track; or a 1100 t train (about 20 cars) to a maximum balancing speed of 143 km/h.

In addition, the DF11 locomotives are designed for Xinjiang, Ürümqi Railway Bureau plateau type of configuration, mainly to increase the output of power, and installation of sound bilateral air intake/air filtration/filter sand unit, and to increase the gear ratio change from 76:29 to 65:22, increasing starting traction and sustained traction. However, the maximum speed is reduced to 153 km/h. Currently, it serves the Guangzhou-Kowloon Through Train.

Major incidents
On 28 April 2008, DF11-0400 locomotive, hauling Train No. 5034, collided with the derailed Train No. T195 in the Jinan-Zibo section of the Jiaoji Railway. The DF11-0400 locomotive was declared destroyed beyond repair and later scrapped.