Public transportation accident in Wenzhou, China
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The Wenzhou train collision was a railway accident that occurred on 23 July 2011, when a high-speed train travelling on the Yong-Tai-Wen railway line collided into the rear of another stationary train on a viaduct in Lucheng District, Wenzhou, Zhejiang province, People's Republic of China. The two trains derailed, and four carriages fell off the viaduct. 40 people were killed, and at least 192 were injured, 12 severely. This disaster was caused by both defects in railway signal design and poor management by the railway company.
The collision is the only fatal crash involving high-speed rail (HSR) in China, and is the third-deadliest HSR accident in history, after the 1998 Eschede train disaster in Germany and 2013 Santiago de Compostela derailment in Spain. High speed was not a factor in the accident, however, since neither train was moving faster than , a moderate speed for a passenger train.
Local officials responded to the accident by hastily conducting rescue operations and ordering the on-site burial of the derailed carriages, allegedly with victims of the accident still inside the carriages. These actions elicited strong criticism from Chinese media and online communities. In response, the government issued directives to restrict media coverage, which was met with limited compliance, even on state-owned networks.
The accident had a profound impact on the development of high-speed rail in China. Public confidence in high-speed rail eroded, resulting in fewer passengers using the service for a short time. Construction of high-speed rail lines in China was temporarily suspended while the accident was under investigation. Speeds on other major high-speed rail lines in China were reduced until improvements were made. China's reputation in high-speed railway technology was scrutinized internationally.
In response to the accident, railways minister Sheng Guangzu announced a comprehensive two-month railway safety review. The official investigation completed in December 2011 blamed faulty signal systems which failed to warn the second train of the stationary first train on the same track, as well as a series of management failures on the part of railway officials in carrying out the due procedure.
The accident led to the implementation of substantial safety improvements, which has so far helped to prevent any further accidents in China's high-speed rail network.
Background.
The Chinese government has invested billions of dollars in the rapid expansion of its high-speed railway network in recent years, including over RMB¥ 700 billion (US$109 billion) on high speed rail in 2010. China's high speed rail now stretches across more than expanding to by 2012, and is planned to double to about by 2020. The nation's entire rail network carried 1.68 billion rides in 2010 with little cause for alarm. The BBC accurately predicted that at this pace, by 2012, mainland China would have had more high-speed railway tracks than the rest of the world put together.
Technology in use.
Signalling.
Railway signalling systems are designed to prevent any train from entering a stretch of track occupied by another train. But in the Wenzhou collision, Train D301 ran onto the track occupied by Train D3115, indicating a signal failure. The 28 July 2011 announcement, by the Beijing National Railway Research and Design Institute of Signals and Communication, that signal equipment had a design flaw, and that it would "shoulder responsibility" for the accident, confirmed that the accident was a result of signal failure.
The signalling technology installed on Chinese high speed lines, including the Ningbo–Taizhou–Wenzhou railway where the accident occurred, is Chinese Train Control System CTCS-2 which is the Chinese version of European Train Control System Level 1. The CTCS-2 system uses the classical technology of track circuits to detect the presence of a train on a piece of track. In addition, CTCS-2 uses both fixed-data balises (track-mounted transponders) and controllable-data balises controlled by a Lineside Electronic Unit (LEU) to transmit essential information and signal instructions from the Train Control Center to trains. Information and signal instructions are transmitted by the balises as "telegrams", which are picked up by a balise transmission module mounted under the head of the train, and sent to an on-board "vital computer" for decoding. Using the data it has received, the computer calculates a "speed control curve" showing the maximum speed the train can maintain while allowing sufficient braking distance before any danger. The information is displayed to the train driver on a monitor. Should the driver disregard this information by overspeeding, or enter a danger zone, the Vital Computer can make an automatic brake application.
As of 31 July 2011, Chinese authorities had failed to provide any logical explanation of why the safeguards built into the CTCS-2 signal technology had failed to work in the Wenzhou collision. Various announcements indicated both defects in equipment (lightning strikes had disabled devices) and defects in operating procedures (staff operated signals in "manual mode"). An Lusheng, the chief of the Shanghai Railway Bureau, was quoted as saying that a device had "failed to turn from green to red". But CTCS-2 equipped trains do not rely on drivers observing green or red wayside signals, the driver has a computer-controlled monitor in front of him. Early announcements spoke of Train D3115 being stopped by a lightning strike, but that would not cause the accident. The second train D301 should not have been allowed to run into it. Whether Train D3115 was stopped by lightning or for any other reason is irrelevant.
The fuzzy and confused official announcements up to 31 July gave increasing hints that a lightning strike caused some wayside-mounted piece of signal equipment to malfunction (the official investigation report in December 2011 identified a trackside LKD2-T1 signal assembly which malfunctioned after being struck by lightning, causing a false indication in the control center that a section of track was unoccupied). If the equipment was not fail-safe, an incorrect response by staff could then cause an accident. Significantly, on 28 July 2011, An Lusheng "faulted the quality of equipment, personnel and on-site controls. He described safeguards as 'still quite weak'."
On 4 August 2011 a high-ranking work safety official ruled out the possibility of natural disaster having caused the train crash. "Now I can say for sure that this is not a natural disaster," Huang Yi, the spokesman and a leading official with the State Administration of Work Safety, said during an on-line chat hosted by people.com.cn, the online arm of "People's Daily". He added that the railway authorities had also pointed out loopholes and deficiencies in safety management, which had emerged in the accident.
The official investigation, completed in December 2011, blamed faulty signal systems which had failed to warn the second train of the stationary first train on the same track, as well as a series of management failures on the part of railway officials in carrying out due procedure.
Rolling stock.
The two trains involved were based on technology from Bombardier and Kawasaki. Train CRH1-046B is a variant of the Swedish Bombardier Regina, while the second train CRH2-139E is a derivative of the Japanese E2 Series Shinkansen 'bullet train.' The Chinese maker has been attempting to patent the same technology and alleged improvements. The trains were of the "D train" class and thus in the first generation of China's express trains, not the faster "G train" class, which travel at more than .
Accident chronology.
On 23 July, at roughly 20:00 CST, CRH train D3115 (CRH1-046B), carrying 1,072 people and travelling from Hangzhou to Fuzhou South came to a halt over a viaduct near the Ou River. Shortly after, CRH train D301 (CRH2-139E), carrying 558 people and running from Beijing South to Fuzhou, crashed into the rear-end of the stationary D3115.
The cause of the crash was initially said to be a lightning strike on one of the line's overhead power lines due to a lightning storm occurring south and west of the viaduct. Lightning reportedly struck the first train, which caused it to stop on the tracks. However, five days after the incident, the Beijing National Railway Research &amp; Design Institute of Signals and Communications Co. Ltd., a railway research institute, claimed responsibility, stating in a report that a signal on the track failed to turn red, and staff failed to notice the error.
A much more detailed description of what happened in the accident, correcting earlier accounts, was published in the December 2011 report of the official investigation. The first train D3115 was stopped not by losing power as a result of the lightning strike, but was stopped by the signal system, the Automatic Train Protection (ATP). The lightning had struck a trackside LKD2-T1 signal assembly, burning out its fuses, and violating the rule that it should be 'fail-safe'. This had caused an incorrect indication in the control center that the track section containing train D3115 was unoccupied (the so-called 'green signal'). The driver He Li of train D3115 worked to override the ATP and, after more than seven minutes of waiting, at 8.29 p.m. he got the train moving again, overriding the ATP. As train D3115 entered the next section of track, where the track circuits that indicate the presence of the train were working correctly, the control center now saw that the track section was occupied. But driver Pan Yiheng of the following train D301 had already been given instructions to proceed onto the section of track where D3115 had been stopped, when the control center had a false indication that the track was unoccupied. Despite a message from the control center that D301 should proceed with caution, less than half a minute later train D301 running at collided with train D3115.
The fifteenth and sixteenth coaches at the rear of D3115 and the front four coaches of D301 were derailed – four coaches fell off the viaduct. Three carriages came to rest horizontally on the ground below while the fourth came to rest vertically, one end on the ground and one end leaning against the viaduct. 
Soon after the accident, the damaged railway carriages were seen being broken apart by backhoes and buried nearby.
The medical teams responding to the accident consisted of staff from Zhejiang No. 1 Hospital, Zhejiang No. 2 Hospital, Zhejiang Provincial People's Hospital and Taizhou Hospital. The evening of the event, 500 Wenzhou residents gave blood in response to early radio appeals by the local blood bank.
A survivor, Liu Hongtaohe, recalled that "the train suddenly shook violently, casting luggage all around. Passengers cried for help but no crew responded" in an interview with China Central Television. CCTV reported on 25 July that the Railways Ministry had declared that 39 people were killed and 192 injured. Two-year-old Xiang Weiyi was the last person rescued, 21 hours after the train crash. Her parents had been killed in the crash.
The U.S. Embassy in Beijing said on 25 July that two U.S. citizens were among the dead. The Italian consulate of Shanghai said that an Italian citizen was among the dead: Assunta Liguori, a 22-year-old student of the Università degli studi di Napoli L'Orientale. Liguori was travelling with Giovanni Pan, a 23-year-old student from L'Orientale, of Chinese origin.
Government response.
Chinese Communist Party general secretary Hu Jintao and Premier of the State Council Wen Jiabao called for "all-out efforts to rescue passengers". Train operations were suspended on the line while damaged infrastructure was repaired. Fifty-eight trains were canceled the following day. Sheng Guangzu, the Railways Minister, ordered an investigation into the accident, and arrived at the scene of the accident on midday 24 July. He also apologised for the accident. Vice-Premier Zhang Dejiang flew into Wenzhou to lead rescue efforts.
The Ministry of Railways announced that three high-ranking railway officials were fired immediately after the crash. They were identified as Long Jing, head of the Shanghai Railway Bureau; Li Jia, party secretary and the deputy chief of the bureau, He Shengli. The Chinese government had sacked railways minister Liu Zhijun in February 2011, for allegedly taking over 800 million yuan in kickbacks connected with contracts for high-speed rail expansion. Zhang Shuguang, the deputy chief engineer of China's railways, was also arrested in February 2011 and alleged to have amassed $2.8 billion in overseas accounts. The government ordered a two-month nationwide safety campaign on 26 July, as the families of victims demanded more answers. Sheng Guangzu apologised for the collision on behalf of the Railways department and said the campaign would focus on improving China's high-speed network.
Government officials had not explained by 25 July why the second train was apparently not warned of the