The Impact of Platform Screen Doors on Rail Capacity

new railway line for commuter trains through central Stockholm, the ‘City line’, is under construction and will open in 2017. The line will have two new underground stations and these will be equipped with platform screen doors in order to enhance air quality and prevent suicides. Several stations along the line will have only two platform tracks and this will limit capacity.

Neither trains nor platform doors will be fully automatized and thus the drivers will have to stop the trains in exact position to match the platform doors. Consequently, adding extended times for opening and closing doors will prolong the dwell time by approximately 12 s/stop.

an extensive capacity evaluation has been carried out as a RailSys simulation in order to find out whether a capacity of 24 trains/hour/ direction can be reached. The core part of the study was to prepare dwell time distributions for all stations along the line. These distributions include several terms, namely additional braking time due to a more careful and precise braking, time to correct stopping position (stochastic), door opening time, passenger exchange time (stochastic), door closing time, door obstruction time (stochastic) and driver’s reaction time before departure.

The simulation results indicate that the extended dwell times caused by the platform screen doors limit capacity to 22 trains/hour in one direction and 24 trains/hour in the other direction. This difference comes from the fact that the station with the longest dwell times is located adjacent to a station with four platform tracks where trains can recover delays. Thus, the delay level differs significantly between the two traffic directions. This delay difference influences the useful capacity in such a way that the most punctual direction has a higher capacity.