Platform screen doors are sliding panels made of glass or durable plastic installed on train or subway platforms to protect waiting passengers from the tracks below. The doors typically serve as a sort of temporary wall through which passengers can see the tracks and the approaching cars but have no way of accessing them until the trains arrive. After the train’s doors open, the panels on the screen doors slide open as well, allowing boarding and disembarkation.
Safety is the main reason why platform screen doors are installed, and among the safety concerns, suicide prevention ranks highly. Jumping onto the tracks ahead of an oncoming train is a common way for people to end their lives. Cities and local governments often install platform screen doors as a means of keeping passengers safely on the platform, preventing both jumps and accidental falls.
Keeping the rails and the platform separate has numerous other advantages, as well. Platform screen doors often contribute to more controlled temperature environments in indoor or underground platforms, keeping wind from the train from significantly affecting the inside environment. The doors can also help reduce the risk of things being dropped onto the tracks, which reduces cleanup and security costs.
Not all platform screen doors are full-sized; that is, not all stretch from the floor to the ceiling. Some types of doors, known as partial screens or platform edge doors, usually stand taller than the train but leave open space at the top. These convey many of the benefits of full gates but usually at a lower overall cost. Platform gates, on the other hand, usually are only about waist high. Their main function is to prevent accidents; intentional jumps and littering are still possible with this setup.
Platform screen doors are most popular in rapid transit commuter systems in Asia, particularly in Japan, South Korea, Singapore and many of China’s larger cities. Similar doors also have been installed in several European rail stations. The costs involved in retrofitting train stations to accommodate metro platform screen doors are often exorbitant, because much of the rail infrastructure would need updating, rewiring and regular testing. For this reason, many transit systems have added the doors to new construction while leaving existing stations as they are.
In North America, platform screen doors are rarely seen outside of airport transit shuttles. This is partly because of the cost as well as the relative newness of many transit systems. It is often a tough sell to convince the operators of systems that are only decades old to engage in major construction projects that would inconvenience commuters and lead to delays.