EN 50155 Certified Computing for Railway Digitalization Projects

Rolling stock modernization programs keep adding computing hardware to trains and trams: onboard video surveillance, passenger information displays, condition monitoring sensors, and real-time links back to a control center. None of that equipment survives long if it is specified the way an office server room would be. A rail vehicle vibrates continuously, runs on DC power that surges and dips in ways road vehicles rarely see, and swings between a cold platform start and a hot, enclosed equipment compartment within the same day. EN 50155 exists because general industrial computing standards do not address any of this, and for most rolling stock procurement in Europe, and an increasingly common baseline elsewhere, it is not optional documentation but a gating requirement before hardware can go onboard.

The Environmental Case for a Dedicated Rail Standard

Rail vehicles subject onboard electronics to continuous mechanical stress that stationary industrial equipment never experiences: the rolling and pitching motion of the vehicle, plus vibration from the track and wheel interface, loosens connectors and fatigues solder joints over years of service in a way that occasional industrial vibration does not. Power quality compounds the problem. Rolling stock typically runs on 24V, 72V, or 110V DC systems, higher voltages than most road vehicle electronics, and that supply is prone to surges, dropouts, and transients that require dedicated protection circuitry rather than the simpler power filtering adequate for a fixed industrial installation. Temperature range adds a third dimension: equipment has to function reliably from a cold outdoor start through a hot, sealed equipment compartment, commonly specified across a range as wide as -25°C to 70°C without active cooling, since fans are generally avoided in rail electronics to eliminate a moving part that dust, vibration, and maintenance access constraints make impractical to service.

EN 50155 is the standard that defines test and design requirements across exactly these conditions, thermal performance, mechanical shock and vibration, humidity, electromagnetic compatibility, and power supply behavior, for electronic equipment installed on railway rolling stock. Equipment carrying EN 50155 certification has been tested against these conditions specifically, rather than certified to a general industrial standard and assumed to be "close enough" for rail use.

What Certification Does and Doesn't Cover

EN 50155 certification is not a single pass/fail stamp that guarantees a computer works in every rail application; it certifies that the equipment meets specific, documented requirements across the categories above, and buyers still need to confirm which sub-requirements and temperature or vibration classes a given product was actually tested to, since the standard allows for different severity classes depending on where in the vehicle the equipment is mounted. EN 50155 also does not, by itself, address fire and smoke safety of onboard materials; that is covered separately by EN 45545, which governs flammability and smoke toxicity of materials used in rail vehicle construction, and by EMC-specific standards such as EN 50121 covering electromagnetic emissions and immunity at the vehicle level. A rail digitalization project procuring onboard computers typically needs to confirm compliance with more than one of these standards depending on the application and the vehicle type, not treat EN 50155 as a complete substitute for the others.

Connector choice is a smaller but practical detail that follows directly from the vibration requirement: standard commercial I/O connectors can work loose under sustained rail vibration, so EN 50155-certified equipment commonly uses M12 locking industrial connectors for network, power, and camera interfaces instead of the friction-fit connectors found on general-purpose computers. This is a design detail worth confirming during procurement, since a computer that is certified to EN 50155's electrical and thermal requirements but retains standard connectors may still be vulnerable to connection failures in service.

Application Areas Driving Onboard Computing Demand

Railway digitalization programs are adding onboard computing across several application categories at once, and each has slightly different requirements beyond the baseline EN 50155 certification. Onboard video surveillance and network video recording require sufficient local storage and multi-camera input capacity, along with reliable operation in a continuously running, unattended state for months between maintenance windows. Passenger information systems need dependable wireless connectivity, LTE, Wi-Fi, or equivalent, to synchronize route data and announcements with trackside and depot infrastructure in near real time. Condition monitoring and train management applications pull sensor data on door status, speed, and system health into onboard processing, feeding predictive maintenance programs that are increasingly central to how operators justify digitalization spending in the first place.

What to Confirm Before Specifying Onboard Computing Hardware

Rail projects should start hardware selection from the vehicle's DC input voltage and the applicable EN 50155 temperature and vibration class for the specific mounting location, since equipment certified for one part of a train is not automatically appropriate for every location on it. From there, the relevant questions shift to the application: camera channel count and storage capacity for NVR use cases, wireless module options for passenger information and fleet management, and confirmation of any additional certifications, EN 45545 fire safety or EN 50121 EMC, that the specific project or region requires alongside EN 50155. Long-term product availability deserves particular attention in rail procurement, since rolling stock frequently stays in service for well over a decade, considerably longer than a typical computing hardware refresh cycle, so a vendor's commitment to long-term support and spare parts availability matters as much as the initial certification.

Frequently Asked Questions

Q: Is EN 50155 certification required for every piece of electronic equipment on a train, or only certain systems?

A: Requirements vary by project, region, and vehicle type, but EN 50155 generally applies to electronic equipment used for control, regulation, protection, diagnostics, energy supply, and communication on rolling stock. Most European rolling stock procurement treats it as a baseline requirement for onboard computing, though the specific severity class required can differ depending on where in the vehicle the equipment is installed.

Q: What's the difference between EN 50155 and EN 45545 for a rail computing project?

A: EN 50155 covers the electronic equipment's own performance under rail operating conditions, thermal, mechanical, electrical, and EMC behavior. EN 45545 is a separate standard covering fire safety of materials used in rail vehicle construction, including the flammability and smoke toxicity of the equipment's housing and internal materials. A rail computer intended for onboard use frequently needs to satisfy both standards, not just one.

Conclusion

EN 50155 certification is the baseline that separates a computer genuinely engineered for rail service from an industrial computer that merely tolerates rail conditions in testing but was not designed around them from the start. Railway digitalization projects, whether adding video surveillance, passenger information systems, or condition monitoring, should treat certification as a starting filter, then confirm the specific temperature and vibration class tested, whether EN 45545 fire safety and EN 50121 EMC compliance are also required for the project, and whether the vendor can commit to the long-term parts and support availability that a rolling stock program's multi-decade service life demands.

ARBOR Technology manufactures EN 50155-certified railway box PCs, including the ARES-1970E-M12-NVR built around M12 locking connectors and PoE camera ports for onboard NVR deployments, giving rail integrators a certified computing platform to evaluate against a project's specific vehicle voltage, camera, and connectivity requirements.