Door systems
A railway door system is the powered mechanical assembly that controls passenger access at the bodyside entrance of a rolling stock vehicle, encompassing the door leaf or leaves, the actuation mechanism, the door control unit (DCU), and the associated safety interlocks.
Three main mechanical configurations are used in European rolling stock. Sliding doors move parallel to the vehicle body along a track or roller guide and are the predominant type in suburban, regional, and metro vehicles, valued for reliability and low maintenance.
Door types
Plug doors move outward before sliding, creating a flush exterior surface when closed; they provide superior aerodynamic sealing and are standard on high-speed trains and vehicles where pressure resistance is required.
Plug-in doors rotate outward and then slide, occupying less internal space in the vestibule than equivalent sliding-door designs, and are commonly used in regional multiple units with limited vestibule area.
Regulatory framework
EN 14752:2019+A1:2021 (Railway applications — Bodyside entrance systems for rolling stock) is the current European standard for design, operational, and test requirements across all passenger door types on tram, metro, suburban, mainline, and high-speed vehicles. It applies to newly designed vehicles and to existing vehicles undergoing door equipment refurbishment, to the extent practicable.
TSI LOC&PAS (Technical Specification for Interoperability — Locomotives and Passenger Rolling Stock, Commission Regulation (EU) No 1302/2014) clause 4.2.5 includes requirements for door control logic in the interoperability context: doors must be locked during train movement above a defined threshold speed; selective door opening — enabling only doors on one side to open at a given station — must be controllable from the driver’s cab.
The TSI PRM (Technical Specification for Interoperability relating to Persons with Reduced Mobility, Commission Regulation (EU) No 1300/2014) specifies minimum door clear-opening widths and step-gap tolerances at boarding.
Control and safety
The DCU manages the open/close sequence, monitors obstacle detection sensors in the door edge, and communicates door status to the Train Control and Management System (TCMS). Door-status information is a mandatory TCMS input for traction interlock: train movement is inhibited while any door is not confirmed closed and locked.
Obstacle detection systems use pressure-sensitive edges, light curtains, or combined electromechanical sensors; sensitivity thresholds are type-tested per EN 14752. DCUs comply with EN 50155:2017 for electronics and must meet the diagnostic and data-logging requirements that allow maintenance teams to retrieve door-event histories.