How to Prevent the Subway Platform Screen Door Accidents?

On January 22, 2022, an old woman on Shanghai Metro Line 15’s Qi’an Road Station tragically got caught by a screen door when she was getting off the train. The train started running normally despite the subway staff trying to help her out of trouble. After the rescue attempt failed, the woman eventually fell into the tunnel as she was driving away from the station and passed away. Why do screen door accidents still happen? The Ministry of Transport requested strengthening the operation and administration of the subway in response to the 1.22 incident in the Shanghai Metro to protect the safety of passengers’ lives. 

There are several possible reasons why the passenger in this incident was trapped: either she got off the train after the alarm sounded, which trapped her when the screen door closed normally; or the subway screen door system malfunctioned and suddenly closed.

In either case, subway staffs are strictly trained and they should know how to deal with emergencies in the event of such an accident. Another staff of Shanghai Metro once said in an interview: “After the accident, the subway station attached great importance to it, and strengthened the training of employees, and emphasized that the emergency stop button should be pressed first in the event of an accident.” According to the analysis of professionals in the industry, there may be two reasons for the Shanghai accident: one is equipment failure and the other is operator error.

A lot of screen door accidents happened

It is not the first time the passengers trapped in screen doors have occurred. In 2007, also in the Shanghai subway, a male passenger insisted on getting on the train despite the alarm sounding, but he did not squeeze into the carriage because there were too many people in the compartment. At this point, the screen doors closed, the train started running, and the passenger was eventually drawn into the tunnel and died. A similar incident occurred in Beijing in 2014. On Beijing Subway Line 5, a woman got caught between a closed screen door and a train door, and she fell into the tunnel and died after the train started running.

These subway accidents have similarities, but they are not the same. They are not caught by the train door but between the screen door and the train door. When the screen door is closed, the train can run normally, resulting in those tragedies. Why can the train start running normally after the passengers get caught? Under normal circumstances, there is a gap in the screen door after a person is caught, and the train should not run. The reason for the train starting running is likely to be a train failure or an operator error, failing to realize the equipment linkage of the driverless train.

So why do screen door accidents occur frequently?

To figure out these questions, first, we need to find out what a screen door system is. The subway screen door is a facility next to the subway platform. It separates the train running area from the passenger waiting area. It plays an important role in the subway system: on the one hand, it can prevent the high-speed train from causing damage to passengers, to guarantee the safety of passengers; on the other hand, it provides a closed environment for the operation of the subway, which can prevent the outside air-conditioning from entering the tunnel and causing damage to the train, to save energy. The subway screen doors ensure that passengers have a safe and comfortable subway-riding environment.

According to Wikipedia, Platform screen doors (PSDs), also known as platform edge doors (PEDs), are used at some train, rapid transit, and people mover stations to separate the platform from train tracks, as well as on some bus rapid transit, tram, and light rail systems. Primarily used for passenger safety, they are a relatively new addition to many metro systems around the world, some having been retrofitted to established systems.

The doors also pose safety risks. The primary risk is that people may be trapped between the platform doors and the train carriage, and be subsequently crushed when the train begins to move. Cases of this happening are rare and may depend upon door design.

So, how does the subway screen door work? The door body consists of three parts, including a sliding door, a fixed door, and an emergency door, among which the sliding door will be opened when the train arrives at the station. When the train reaches the platform and is aligned with the screen door, the train door and the screen door will be opened almost at the same time. At this time, there will be a broadcast in the subway reminding passengers to get on and off the train, then passengers will start to get on and off the train in sequence.

How can we prevent getting caught?

How should we learn lessons from those subway accidents and avoid being caught while riding the subway? As a passenger, we must first abide by the rules of the subway and not forcefully get on and off the train because of a rush. We may lose lives if we forcefully get in and out. When a crowd of people is waiting to get on and off the train in front of the subway door, we must strictly abide by the rules of getting off first and then getting on to avoid crowding at the door. Also, be careful not to lean on the door while the train is running, to avoid falling into the tunnel if the door is suddenly opened.

The screen door was initially set up to ensure the safety of passengers. The screen door will lose its original meaning if safety accidents occur frequently. While passengers increase their awareness of abiding by the rules of riding the subway, the subway must also strengthen safety training for staff to prevent such incidents from happening again. At the same time, the subway system also needs an automatic mechanism, that is, when the screen door has an abnormal condition, the system detects an abnormal condition, the screen door cannot be closed, and the train cannot run so that the accident will not happen.

China is a country with a large population. In some large cities, the passenger flow is huge, which often induces passenger trapping accidents due to the obstacle detection sensitivity of screen doors. At this time, it is necessary to optimize the obstacle detection system! The lidar sensor can accurately scan and detect the situation of the screen door, which can not only improve the sensitivity of the screen door obstacle detection but also ensure the safety of passengers.