Railway mine area China pain points

A series of question marks triggered by the July 23 accident in Wenzhou have not yet been well answered.

In addition to the list of casualties, what people are most concerned about is the real cause of the accident.

The Chinese railways, especially the rapid railway and high-speed rail, are really vulnerable to lightning strikes. The media reports all pointed out that the failure of a railway signal caused by a lightning strike was a necessary condition for the accident. This incident also has the "red light with a fault" statement.

In addition to these factors, there are other hidden concerns that must be addressed?

Cui Wei, a reporter from the newspaper, Yan Youliang, three years ago, a cement accident took place on a temporary line with a speed limit of 4.28 accidents; three years later, a high-speed new line that had been in operation for less than two years became a land of death.

At 20:30 pm on July 23, a rear-end collision occurred between the D301 train from south Beijing to Fuzhou and the D3115 train from Hangzhou to Fuzhou. The driver Pan Yiheng took emergency braking measures but failed to stop the fatal disaster. The four cars of the D301 train fell from the overhead frame. As of press time, 39 passengers and crew members have been declared dead and 192 injured.

According to the document of the Ministry of Railways, this is an extremely serious accident.

In the past three years, the trains have been substantially accelerated, and the train automation system has covered all electrified railways. However, the technological system in progress has failed to stop the disaster.

Lightning Protection System, Train Automatic Control System, Automatic Blocking System (ZPW), Train Automatic Protection System (ATP), Train Operation Monitoring and Recording Device (LKJ) and a series of railway defense lines that make railway people proud Sudden lightning completely broke.

The accident has been peeling off layer by layer in recent days, and more and more information has been directed at the fragile railway signal system and chaos. The problems exposed by the July 23 accident have precedents on the Chinese railways.

“The safety and security of China’s high-speed rail is reliable.” He Huawu, chief engineer of the Ministry of Railways, announced in a firm voice at the third International Conference on Transportation Engineering held in Chengdu on July 23. At that time, he faced a series of late accidents since the Beijing-Shanghai high-speed railway began on July 10.

Shortly after the voice fell, a rear-end collision occurred.

Reproduce "lightning strike theory"

At 18:21 on July 24, the last damaged car was lifted off the rail viaduct. Soon, the wind raged, heavy rain poured, thunder and lightning. One day ago, the same happened in the local area.

“At that time, it felt like the sky was going to blast.” The worker of the Ding Lifeng Shoes Factory told the Times Weekly reporter.

The Wenzhou Metropolis Daily, which first reported the cause of the July 23 accident, stated that it was the raging thunder and lightning that hit the D3115 train, causing it to lose power and stop, followed by D301 follow-ups.

This explanation once confuses many people.

"If the D3115 loses power and shuts down, then why did the D301 that entered the same sector open so fast, then hit it?" A netizen questioned on Weibo.

The emergence of another train D3112 let people solve the mystery.

On the second day of the accident, passengers from the D3112 train posted on the Internet and said that on the night of the accident, the D3112 train was struck by lightning, stopped and stopped earlier than the rear-end collision, and this train was After being forgotten by everyone. The railway timetable shows that D3112 flights from Fuzhou South to Hangzhou are in the opposite direction from the D301 and D3115 times that occurred after the rear-end collision. The time that passes through Wenzhou South is 18:53.

On the afternoon of July 25th, when the reporters found Lu Qingxiang, the head of the Wenzhou South Station, he confirmed that the D3112 trains did experience lightning strikes and malfunctions on July 23. After the main power was exhausted, the car was stopped. Then the passengers returned on foot to Wenzhou South Railway Station.

At the same time, some passengers also reported that D3115 power was normal before the rear-end collision and no power cuts occurred.

After this situation was revealed, more people tended to think that the severe lightning strike encountered by D3112 was the real cause of the accident.

However, many experts believe that lightning is a small probability event.

“The possibility that a motor vehicle is struck by lightning directly is not great, and the railway itself also has a perfect lightning protection system. However, some lightning, such as rolling mines, threaten the catenary and the motor vehicles very much, and it is possible to directly breakdown.” Academician of the Academy of Engineering said in an interview with Times Weekly.

“The probability of a train being struck by lightning is indeed very small, but it is clear that the research and development of lightning protection devices for motor vehicles should be strengthened. In particular, the forecasting work should be strengthened and decisively suspended at certain times,” said Guan Xiangshi, member of the National Technical Committee for Lightning Protection Standardization.

In fact, lightning protection devices including lightning rods, lightning conductors, lightning protection nets, lightning arresters and other lightning protection devices have been widely used along railway lines, but lightning accidents still occur frequently. The occurrence of outage accidents due to lightning strikes occurs every year.

In June and August last year, the Quanzhou section and the Hefei section of the railway were all suspended due to lightning strikes.

“The railways it achieved are still very afraid of lightning strikes, because computers and other equipment are already the main equipment for railway operation, and the lightning protection facilities have not kept up with it in a timely manner. Once lightning strikes computer equipment, it is easy to paralyze, and then affects the trains on the line.” Beijing A person working in the shunting work at the Fengtai West Railway Station of the Railway Bureau told reporters.

However, for such a common problem, the Ministry of Railways has no specific emergency measures in the country except in the southwest mountainous areas where lightning is frequent. The only relevant “Emergency Preparedness Plan for Severe Weathers such as the Railway Storm, Snow and Fog” (temporary) only mentioned that “in the event of a lightning strike, all telecommunications and power supply departments must strengthen inspections to ensure that the electricity, power supply equipment, and contact network equipment are in good condition”.

As for whether there are temporary outages in lightning weather, there are no regulations to follow.

Red light with doubt clouds

Lightning strikes are just the beginning of things.

Only the loss of power caused by lightning strikes will only be like the armpits of trains. Lines will be out of service for two or three hours. It is hard to think of this rear-end disaster. Moreover, the D3112 train that was struck by lightning is still away from the accident site. Five kilometers away, there was no involvement in the accident.

"Under normal circumstances, it is impossible for an EMU to collide with a tail-end accident unless there is a problem with the signal system." Wang Mengshu speculated on the second day of the accident.

Subsequent media reports all pointed out that the failure of a railway signal caused by a lightning strike was a necessary condition for the accident.

Red band failure is the most common manifestation of railway signal failure. “Red light” is used to identify the train coordinates in the monitor of the railway control system. Because the rail itself belongs to the conductor, the position of the train can be displayed once the train wheel pair contacts the rail and forms a loop. However, if the rails are short-circuited due to insulation failure without passing through the car, a red band or reddish area will appear on the monitor. The red band is extremely complex and can be caused by moisture, lightning, and insulator breakdown. Similar faults.

"First Financial Daily" quoted a professional analysis that lightning strikes may have caused a red band near the southern Wenzhou area, and this statement is also widely circulated in the Railway Forum.

In the event of a red belt failure, the railway's Automatic Blocking System (ZPW) is not able to operate normally. It is not possible to allow the train to pass at full speed, either to stop and wait for fault repair, or to switch from a full monitoring mode to a visual driving mode. The speed is reduced to The speed of 20 km/h can be parked at any time.

The rear-end accident occurred just after D3115 entered the red zone.

On July 26, Yang Yanxia, ​​the surviving passenger and accident survivor of D3115, told the Times Weekly that the train speed was very slow. Another passenger, Zhuo Xiuzhen who boarded from Ningbo, pointed out that the train was "walking for a while and stopping for a while." Another witness, who was standing at the Dinglifeng Shoes Factory on the fourth floor of a residential building near the scene of the accident, told the Times Weekly reporter clearly that the train in front of him had stopped for a while and slowly moved forward. One minute later, there was another motor car.

If the above-mentioned passengers' memories are accurate, the D3115 traffic condition at that time basically coincides with the visual driving mode.

The situation encountered at D3115 was not the first time it occurred on the railway.

Compared with lightning strikes and power cuts, accidents caused by red light faults are much more serious, and they are often the result of train rear-end collisions.

On April 11, 2006, two bus collisions occurred in the Longchuan section under the Guangmei-Chongqing Railway Company. T159 times hit 1017 stops from the rear, resulting in the derailment of several cars and the death of two crewmen. There were more than 20 people. Injured.

According to a technical exchange document of the Beijing Communications Signal Design and Research Institute in November 2008, the cause of the accident was an abnormal red band due to the low resistance of the road during the rainy season. This document also disclosed that in July 2005, the Xin Jun Shimiao tunnel of the Xi'an Railway Bureau also caused a train rear-end collision due to a red light belt failure. The reason was that the ballast resistance was low.

According to the data, the ZPW-2000A non-insulated frequency-shifting automatic blocking system was used on the Wenzhou-Wenzhou Railway.

According to the “People's Railway” report in the 4th issue of 2010, the red band of the track circuit of the ZPW-2000A system has frequently occurred, which caused a major technical problem for the staff of the Changzhou Electric Railway.

"The ZPW-2000A non-insulated frequency-shifting automatic blocking system has been identified by the Ministry of Railways as a unified system for the automatic blockage and development of China's railways in the future with its high safety, high anti-interference, high transmission performance, high system reliability and low construction cost." China Railway Communication and Signaling Group introduced ZPW-2000A on its website.

“The red band is really an insurmountable problem, because the causes of the red band are very diverse, and the results shown are the same. Only the site can be determined by careful investigation.” No one in the Beijing Communications Signal Design Institute Will be named experts say to the Times Weekly.

Dispatch responsibility

After D3115 entered the suspected red band fault zone, D301 exited at Yongjia station at 20:24.

From the train timetable of the Ministry of Railways, D301 should have arrived in Wenzhou South at 19:42, and D3115 should arrive at Wenzhou South at 19:57, which is later than D301. But at this time, D3115 times was ahead of D301, and the D301 delay was more serious.

In the general terminology of the railway system, the next two vehicles appeared within the same “blocked area”, which was a serious departure from the technical regulations of the railway and would never have happened under normal circumstances.

According to the operation principle of the Automatic Blocking System (ZPW), the interval line between each two stations is divided into a number of small sections called "occluded areas". When there are other trains in the block area ahead of the train, the following trains It is necessary to automatically stop and wait in order to effectively prevent accidents such as rear-end collisions. The distance of each “occlusion area” is determined by the speed of the road section. Usually, the distance of the block area is the minimum allowable distance between the two workshops.

Wang Mengshu introduced that the automatic blocking system requires no vehicles within 6 km to operate. The yellow light is on within 4 km from the vehicle in front, prompting deceleration, and a red light will be displayed when the distance is 2 km.

The distance from the Yongjia station to the accident site is 13 kilometers, which happens to be two occlusion areas. Under normal circumstances, the rear-end accident cannot occur.

However, under the fault of the red belt, the automatic blocking system obviously has failed because the automatic train control system has failed to correctly identify the position of the train, and the signal lamp of the road section is likely to be in a disordered state.

In this case, the D301 train that is about to enter the fault zone of the suspected red zone should be changed to the visual mode as D3115 and the speed will be reduced to 20 kilometers per hour.

However, D301 did not decelerate after opening.

Many people suspect that there may be a lightning strike that caused the D301 to lose contact with the dispatch center.

However, according to the "Jinghua Times" quoted a foreman of the Wenzhou Communications Workshop of the Shanghai Railway Administration on July 27, the communication system of the D3115 train was not damaged after the incident. Therefore, the driver can normally communicate with the vehicle dispatcher.

More people are wondering about the inability to communicate between D301 and D3115.

“Even if the communication equipment fails to contact the dispatcher, the driver has to carry the mobile phone. Why don’t you notice it?” one netizen questioned.

"D3115 driver does not even know who is behind the D301 driver. How could he possibly call the mobile phone? The public does not understand the schedule of the railway. The driver only needs to report with the dispatch center. The driver can only follow the instructions of the dispatcher, and he can't do it himself. Decided.” The Fengtai West Station said to reporters, “This situation is likely to be a matter of scheduling problems and not promptly sending D301 a speed reduction order.”

This time, the Ministry of Railways also revealed information about the accountability of Shanghai Bureau of Railways in the personnel appointment and dismissal of the Shanghai Railway Administration after the accident, and the dispatch has always been attributed to the management of telecommunications.

The three leaders of the Shanghai Railway Bureau who were dismissed after the accident included He Shengli, the deputy director in charge of electrical affairs, and Anluo Sheng, who was parachutized by the Shanghai Railway Bureau, as the general dispatcher of the Ministry of Railways twice. However, An Lusheng's two adjustments from the general dispatcher's position to the local road bureau were all due to the occurrence of a major railway accident. This time, the repeatedly-accredited An Lusheng had been questioned by many for his management of chronic diseases. ability.

Final insurance

The automatic train protection system (ATP) and the train operation monitoring and recording device (LKJ) have long been considered to provide security for high-speed trains.

The ATP system consists of trackside equipment and on-board equipment. Trains receive target speeds running in this section through ground equipment to ensure that trains do not exceed the target speed, thus ensuring the connection between subsequent trains and preceding trains. Safety clearance distance.

The LKJ system is even more capable of rectifying the driver's wrong operation.

However, on the evening of the 23rd, the D301 ATP and the LKJ system did not allow the train to recline.

For the D3115, switching to visual traffic mode will shut down the operation of the ATP, and as a part of being rear-ended, its protection system won't have any effect even if it is turned on.

However, D301's protection failure has always been considered difficult to understand.

"This possibility of failure of the follow-up train ATP function is very small." Xie Weida, executive deputy director of the Institute of Railway and Urban Rail Transit of Tongji University, introduced.

As a member of the ATP equipment manufacturer, Hollysys Group executives declared to the “Oriental Morning Post” that the company had dispatched related technical personnel to Wenzhou on July 24th. The current test data indicates that the on-board system is operating normally. The accident has nothing to do with profit.

The train driver may be the last line of defense to protect the train.

At railway forums familiar to railroad staff, there are many speculations that the D301 ATP system may be artificially isolated.

“I think this kind of speculation is ridiculous. Even if it is already late, the driver cannot drive in such a life-threatening manner. Who would have ignored his life? Moreover, there is still no conclusion that D301 driver Pan Yiheng should be responsible for the accident. A netizen who claimed to be a train driver told reporters via text message .

Wang Mengshu stressed that after the accident, fatigue operation errors may be one of the causes of the accident. Despite this statement, many railway employees are dissatisfied, but in an interview with the Times, Wang Mengshu still insists on this point of view.

"The problem of fatigued driving is very common in previous accidents. The pressure of the train driver itself is very large. It will not change for such a long time," Wang Mengshu said. At the time of the accident, D301 trips from Beijing had been running for nearly 12 hours.

Peng Qiyuan, dean of the School of Transportation at Southwest Jiaotong University, also revealed that the single-sector mechanism is now used for motor vehicles.

Many railroads also reported online that before the train had a deputy driver, the deputy driver in the train had gradually been cancelled.

Despite this, D301 driver Pan Yiheng took an artificial brake at the last minute of his life. According to Wang Mengshu, at least, the speed was reduced by 40 kilometers. "Otherwise, the consequences will be even more serious."

Another D3115 driver who has not yet been identified by the public has not shown up after the accident. According to sources in the “Nanjing News” quoted by the Nanchang Railway Bureau, the D3115 train driver is currently under investigation by the State Council investigation team.

After 0:00 on July 26th, a netizen claiming to be a D3115 driver friend appeared on Weibo. The netizen who was later renamed “Statement 918” subsequently provided a conversation record with the D3115 driver, which mentioned that The driver once reported that the interval signal was unstable at Wenzhou South Station at 20:20. He had learned from the dispatcher that "D301 is 20:24 on." He thought that the reason for changing to the visual driving mode was "usually the rear train." The track needs to be replaced when it exceeds the front."

"I don't know where things are going to be serious. I don't know what results will be given to me. I just feel sorry that this kind of thing can be avoided completely. One or two chances won't explain perfection." The driver finally Say to my friend.

The reporter has repeatedly contacted “Statement 918” to verify his identity, but he has not yet received a reply.