EN 50155 specifies the requirements for design, manufacturing, documentation and testing of any electronic equipment installed on-board of rolling stock. It also describes the electrical and environmental operating conditions. This standard applies to all electronic equipment for control, regulation, protection, diagnostic, energy supply installed on railway vehicles and any relevant elements of rolling stock subsystems (for example external doors, On-Board ETCS functionality, wheel slide protection).
For the purpose of EN 50155, electronic equipment is defined as equipment composed of electronic components (for example resistors, capacitors, transistors, diodes, integrated circuits, hybrids, application specific integrated circuits, wound components and relays) and recognised associated components (for example connectors, mechanical parts). These components are mainly mounted on printed circuit boards. Sensors (like current, voltage, speed) and semiconductor drive units for power electronic devices are also covered by EN 50155. Complete semiconductor drive units and power converters are covered by EN 61287-1.
Specific requirements related to practices necessary to ensure defined safety integrity level or functional safety are not covered by EN 50155. Nevertheless, this standard applies to the hardware of all rolling stock electronic equipment or systems performing safety-related functions. The software development requirements for on-board railway equipment are specified by EN 50716.
