Electronic equipment used on rolling stock (printed-circuit-board components, sensors, semiconductor modules) - temperature, power supply, vibration, EMC.
The standard covers the design, manufacture, documentation and testing of electronic equipment installed on railway vehicles: control, regulation, protection, diagnostics and power-supply systems. Electronic equipment within the meaning of the standard consists of electronic components (resistors, capacitors, transistors, diodes, integrated circuits) mounted on printed circuit boards; the standard also covers sensors (current, voltage, speed) and semiconductor control modules.
Complete power converters are within the scope of EN 61287-1, while SIL and software requirements are covered by EN 50716 (formerly EN 50657). Electromechanical apparatus (relays, contactors, circuit-breakers) and fuses do not fall within the definition of electronic equipment - their product standard is the IEC/EN 60077 series (electrical equipment for rolling stock).
The standard applies to rolling stock.
An EN 50155 declaration stating an OT temperature class and a power-supply class means the electronics have passed the environmental, power-supply and EMC tests required for rolling stock; for electromechanical apparatus, IEC/EN 60077 fulfils an analogous role.
The scope covers electronic equipment: printed-circuit-board components, sensors and semiconductor modules. Electromechanical apparatus and rolling-stock fuses have their product standard in the IEC/EN 60077 series.
CENELEC ratified EN 50155:2026 (publication July 2026); the 2021 edition is in a transition period. Data sheets often still refer to EN 50155:2017 - the date in the declaration indicates which edition was used to test the product.
The OT ambient temperature class defines the operating temperature range over which the product has passed testing; the class is selected according to the installation location in the vehicle. Similarly, the power-supply class describes immunity to fluctuations and interruptions in the onboard supply voltage.
