For those who are accustomed to riding MRT Jakarta may already know one of the rules that applies to passengers, to not to lean on the platform door. But do you know why? In some MRT stations, the platform door turns out to be not an ordinary barrier. It has an important function in the MRT system.

Platform Screen Door or PSD imits platform area to railroad tracks. The main function of PSD is to guarantee passengers safety. The risk of passenger falling into a railroad track or being pinched can be suppressed with the help of PSD. Quoted from PT MRT Jakarta official website, as many as six underground MRT stations are installed with a two meter high PSD, while seven elevated stations are fitted with 1.3 meters PSD. All PSDs are made using clear glass that is vibration resistant.

Some PSDs are Automatic Sliding Door or ASD equipped with sensors to prevent passengers from being sandwiched between doors. In addition, the ASD is also equipped with indicator lights and loudspeakers as open or closed door signs. Interestingly, this door turned out to have been connected with a train signaling system, called communication-based train control.

The door can detect when the train will come or go, so it will open and close automatically along with the opening and closing of the train door. This feature also causes the position of the train door is always right facing PSD. That is why passengers are prohibited from leaning on, feared it will causing interference on the PSD.