The heavy rain in Zhengzhou on July 20 was known as a once-in-a-millennium event and caused serious floods. Among them, more than 500 people were trapped on Zhengzhou Metro Line 5 and 12 people died.Regarding this accident, People’s Daily Online quoted Meng Yi, an expert on urban public transportation and rail transit for 22 years, and summarized several reasons, including natural disasters, linkage mechanism and vehicle design flaws.
Meng Yi said, “The core of this accident is a natural disaster of the once-in-a-millennium level.”
In Meng Yi’s view, even the Zhengzhou Subway, which was designed and constructed in accordance with the 200-year flood control standard, was difficult to make up for in the face of this heavy rain.
Meng Yi said: “The disaster is the core reason that caused the serious irrigation of Zhengzhou subway and the tunnel became a’sewer.’ The flooding of the subway is not due to human beings, nor is it something human technology can resist at this stage.”
In addition to the extremely heavy rain that has occurred once in a thousand years, Meng Yi believes that the accident also exposed the problem of the lack of a linkage fuse mechanism.
He said: “Judging from the accumulated precipitation in Zhengzhou before the accident, it has already exceeded the Zhengzhou subway fortification standard. If the outage dispatching was organized at that time, the trains would stop at the station and no longer depart at the station. At the same time, passengers would still be allowed to be cleared. The station is sheltered from rain. Although the station and tunnel will still be flooded, the difficulty of rescue and casualties will be greatly reduced, and there will be no danger of passengers being trapped in the tunnel.
Meng Yi also believes that in addition to the need to make up for the vacancies in the system, the accident exposed the “malfunctions” in the train design.
In Meng Yi’s view, there is no escape door for the relevant train, which has lost the “golden window” for the safe evacuation of personnel.The controversy that the train did not have the first and last escape doors appeared when Zhengzhou Metro Line 1 rolled off the line in 2012.
He introduced that the relatively high proportion of domestic subway trains operating in underground tunnels determines that vehicle design should pay more attention to evacuation performance. The escape doors located at the head and tail of the train can help passengers evacuate quickly during the initial period of flooding. “The more evacuation channels, the more evacuation channels. The faster the evacuation.”
In Meng Yi’s view, the design of the evacuation platform alone did not take into account the situation when the train derailed and hit the escape platform. He also criticized the above design in professional discussions on many occasions. Therefore, he emphasized that in the future subway vehicle design process, The escape door is essential.
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