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Chongqing–Lanzhou railway is a major trunk railway in China connecting Chongqing and Lanzhou. Construction started in 2010, last segment of the railway was opened for service in September 2017. The line allows trains to travel between Chongqing and Lanzhou, Gansu via Nanchong and Guangyuan, Sichuan.
With a total length of 820 km, of which 435 km is located within Gansu Province, in addition to the construction of a branch to Nanchong and Guang'an that is 95 km long. It was built as a new double line electrified railway, with freight train capable of up to 160 km/h, passenger trains traveling at 200 km/h. The capacity of the line is expected at 50 train pairs per day and 50,000,000 tonnes of freight per year.
Lanzhou–Chongqing railway project was estimated to need a total investment of 77.4 billion yuan, of which the Gansu Provincial Government invested about 43 billion yuan, with the rest of the funding was coming from a Ministry of Railways, Sichuan and Chongqing joint construction effort. The construction period was expected to take 6 years. By the completion of the railway rail transport from Lanzhou and Chongqing is shortened from 1466 kilometers to 820 kilometers, conventional train running time is reduced to 7 hours from 17.5 hours. Fast trains will complete the route in 5.5 hours.
Recent high speed rail reforms has also meant direct Chengdu-Lanzhou and Chongqing-Xi'an services will use a combination of Xi'an–Chengdu high-speed railway and Chongqing–Lanzhou high-speed railway from where they meet at Guangyuan, Sichuan. This will reduce the need for a separate direct Chongqing-Xi'an or Chengdu-Lanzhou line.
Because of hilly terrain between Guangyuan and Lanzhou on 832 km of railway there are 285 bridges totaling 104 km (13% of the route) and 178 tunnels totaling 506 km (63% of the route). Twelve of the tunnels will exceed 10 km in length, while the longest tunnel, West Qinling Tunnel, measures 29 km.
Lanzhou–Chongqing railway runs west out of Lanzhou City through Yuzhong County, Weiyuan County, Min County, Tanchang County, Longnan City in Gansu. Crossing into Sichuan Province territory, it then travels by Guangyuan, Cangxi County, Langzhong, Nanbu County, Nanchong. Finally it enters Chongqing City via Hechuan District and Beibei District before terminating at Chongqing North railway station.
- August 1, 2008, West Qinling Tunnel as the first part of the project is opened for tender and bidding started, marking the start of Lanzhou–Chongqing railway construction.
- July 19, 2014, West Qinling Tunnel construction is completed.
- August 8, 2014, Nanchong East station branch opens with EMU services to Chengdu East 
- January 1, 2015, 70.7 km of the southern end of the project is opened. This allows for Chongqing to Hechuan EMU services in just 20 minutes.
- December 26, 2015, The southern section of the line, from Chongqing to Guangyuan, Sichuan, opened in December 2015. Initially with only conventional rail services.
- May 15, 2016, High speed EMU services commence with train D5131 running from Chongqing to Guangyuan station in a total of 3 hours 06 minutes. It ran at a maximum speed of up to 200 km / h.
- December 26, 2016, The section between Guangyuan, Sichuan and Minxian, Gansu was completed in December 2016. However, due to Minxian's small size and remote location, services will only commence to Longnan.
- September 29, 2017, The section between Minxian, Gansu and Lanzhou, Gansu was completed in September 2017.
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