Integration of Obstruction Detection Function for Passenger Doors on EMU400 Series Trains


Railway safety standard today is higher than twenty years ago. Welltek improves EMU400 Series trains safety for Taiwan Railway Administration (TRA) by integrating obstruction detection function on their passenger doors. EMU400 Series trains were manufactured in 1990s and there are four passenger doors on each train.




Welltek proposed pressure wave sensor to detect obstruction. The pressure wave sensor is very sensitive and reliable.


TRA requests a safety requirement: when any one of the passenger doors is not closed, the trains should not have the motive power to go forward or backward. In that way, the driver and the conductor will ensure that all the passenger doors are closed before the train departures. To achieve this safety requirement, the control of train’s motive power and the controls of the passenger doors should be coupled. 

Solution “Door Obstruction Detection Controller”:

Welltek investigates control circuit diagram of EMU400 Series trains. By combining one 89S51 micro-controller, three relays, two pressure wave sensors, two door rubber seals, and know-how of the EMU400 controls, Welltek develops a door obstruction detection controller, which fully meets TRA’s requirement. 

Welltek designs a door rubber seal as an air container for the pressure wave sensor. If the door hit a obstruction while closing, the shape changing of the rubber seal will push air to the pressure wave sensor. Signaled by the sensor, the micro-controller will then open the door. After a pre-setting time (3 to 18 seconds), the micro-controller closes the door again .



Door Obstruction Detection Controller are successfully integrated into twelve sets of EMU400 Series trains and any two sets of trains can be coupled without adjusting any controller setting.