Harmony bullet trains at a high-speed train maintenance base in Wuhan, Hubei province Tuesday, December 25, 2012. China has the world's longest high-speed-rail network, more than the rest of the world combined. (Photo by Reuters/Stringer)





A construction worker watches a train pass on the high-speed railway line between Shanghai and Hangzhou on the outskirts of Shanghai Tuesday, October 26, 2010. (Photo by Carlos Barria/Reuters)





A driver makes a phone call in the engine driver's cabin of a CRH 380A bullet train serving the high-speed railway between Shanghai and Beijing Wednesday, May 11, 2011. (Photo by Carlos Barria/Reuters)





A train attendant stands inside a CRH 380A bullet train serving the newly built Shanghai-Beijing high-speed railway during its debut test at the Hongqiao Railway Station in Shanghai Wednesday, May 11, 2011. (Photo by Carlos Barria/Reuters)





A train employee walks into the lead car of a Harmony 380BL bullet train at Beijing South Railway Station Friday, August 12, 2011. (Photo by Jason Lee/Reuters)





A driver is seen sitting in the engine driver's cabin of a CRH 380A bullet train travelling on the high-speed railway between Shanghai and Beijing Thursday, June 16, 2011. (Photo by Reuters/China Daily)





A woman takes pictures of the new Beijing-Tianjin Intercity Railway train at the station in Beijing, August 1, 2008. (Photo by Kim Kyung-Hoon/Reuters)





A train attendant helps a passenger to adjust her seat at the business class carriage on a CRH 380A bullet train Thursday, June 16, 2011. (Photo by Reuters/China Daily)





An employee adjusts a CRH380B high-speed Harmony bullet train as it stops for an examination during a test run, at a bullet train exam and repair center in Shenyang, Liaoning province Tuesday, October 23, 2012. (Photo by Reuters/Stringer)





A woman walks into a carriage of a Beijing -Tianjin Intercity Railway train in Beijing Friday, August 01, 2008. (Photo by Kim Kyung-Hoon/Reuters)





Two CRH380A high-speed bullet trains park at Beijing South Railway Station Friday, August 12, 2011. (Photo by Jason Lee/Reuters)





Mechanics examine a bullet train at a high speed railway maintenance station, to prepare for the annual mass migration ahead of the Chinese lunar new year, in Nanjing, Jiangsu province Monday, February 02, 2015. (Photo by Reuters/China Daily)





A Harmony bullet train pulls into Beijing South Railway Station Monday, July 25, 2011. (Photo by Jason Lee/Reuters)





A worker cleans a CRH380B high-speed Harmony bullet train as it stops for an examination during a test run, at a bullet train exam and repair center in Shenyang, Liaoning province Tuesday, October 23, 2012. (Photo by Reuters/Stringer)





A passenger walks past high speed trains at a railway station in Nanjing, capital of east China's Jiangsu province Sunday, April 29, 2007. (Photo by Jeff Xu/Reuters)





Rescuers carry out rescue operations after two carriages from a bullet train derailed and fell off a bridge in Wenzhou, Zhejiang province, July 24, 2011. (Photo by Aly Song/Reuters)





A train employee looks out from an entrance of a Harmony bullet train at Zhengzhou East Railway Station in Zhengzhou, Henan province Monday, February 17, 2014. (Photo by Jason Lee/Reuters)





A worker walks between two bullet trains at a high speed railway maintenance station in Xi'an, Shaanxi province, China Friday, September 11, 2015. (Photo by Reuters/Stringer)





A CRH380BL high-speed bullet train runs towards Beijing South Railway Station Friday, August 12, 2011. (Photo by Jason Lee/Reuters)





A worker stands among Harmony bullet trains at a high-speed train maintenance base in Wuhan, Hubei province Friday, March 13, 2015. (Photo by Reuters/Stringer)