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Guide · Rail & Metro · Built in India
EN 50155 is the European standard for electronic equipment installed on rolling stock (railway vehicles). It sets requirements for operating conditions, design, documentation and testing, covering operating temperature classes, power supply variations and interruptions, shock and vibration, EMC and insulation, so that onboard electronics keep working in the harsh rail environment. IEC 60571 is the closely aligned international standard.
The short answer
EN 50155 (Railway applications, Rolling stock, Electronic equipment) applies to electronic equipment for control, regulation, protection, diagnostics and energy supply installed on rail vehicles. It defines the electrical and environmental conditions the equipment must withstand, together with requirements for design, documentation, testing and integration. The current edition is EN 50155:2021; the 2017 revision introduced the six operating temperature classes used today. Functional safety and safety integrity levels are outside its scope, and software for onboard railway equipment is covered separately by EN 50657.
Why it matters
Passenger information displays, onboard CCTV cameras and recorders, and remote monitoring gateways stay on the vehicle for many years of service. They face wide temperature swings, a battery-fed supply with dips and interruptions, constant shock and vibration, and a dense electromagnetic environment close to traction equipment. Specifying EN 50155 with the right temperature class, supply voltage and mounting location gives buyers and suppliers a common language for these conditions, and a defined set of tests to ask for as evidence.
Key requirements
A summary of what the standard asks of rolling-stock electronics. Always check the exact edition and classes named in your tender.
Six classes run from OT1 (−25 °C to +55 °C) to OT6 (−40 °C to +85 °C). OT1 and OT2 typically suit passenger compartments and driver's cabs, OT3 and OT4 equipment in cabinets, and OT3 (−25 °C to +70 °C) applies unless otherwise specified. Separate switch-on classes cover start-up conditions.
Equipment runs from the vehicle's battery-fed DC supply, with nominal voltages from 24 V to 110 V. It must tolerate continuous voltage variation, short transient dips and surges, supply interruptions graded by class (S1 to S3) and supply change-over, all checked in the power supply tests.
Shock and vibration testing follows EN 61373, with test categories set by where the equipment is mounted: car body, bogie or axle. Electromagnetic compatibility, covering both emissions and immunity, follows EN 50121-3-2 for rolling-stock apparatus.
The standard covers insulation resistance and voltage withstand testing for electrical safety, design practices such as component selection and derating, useful-life classes, and the documentation a supplier is expected to provide with the equipment.
Testing
EN 50155 separates type tests, carried out on representative units to show that a design meets the standard, from routine tests carried out on every unit after manufacture. Type tests typically include visual inspection, performance, power supply, cold, dry heat, damp heat, insulation, EMC, and shock and vibration. Routine tests typically include visual inspection, performance and insulation checks. Which tests and classes apply should be agreed between buyer and supplier at tender stage.
Checklist
Use these points when writing a specification or comparing suppliers. Ask for test evidence for the exact product configuration rather than relying on a datasheet label.
Temperature: which operating temperature class (OT1 to OT6) and switch-on class does the mounting location need, and has the unit been tested to it?
Power: which nominal battery voltage (for example 24 V, 72 V or 110 V DC) and which supply interruption class does the vehicle require?
Shock and vibration: is there an EN 61373 test report for the right mounting category (car body, bogie or axle)?
EMC: is there EN 50121-3-2 emissions and immunity test evidence for the configuration being supplied?
Evidence: will the supplier share the full type test report, name the EN 50155 edition tested against, and provide routine test records for delivered units?
Installation: do connectors, enclosure ingress protection and mounting suit the location, and are fire-safety requirements such as EN 45545-2, often specified alongside, covered?
Lifecycle and sourcing: are spares, repairs and obsolescence support committed for the service life, and does the programme favour Built in India / Make in India manufacturing?
Envision TechWorks
Envision TechWorks products are designed, manufactured and tested in an ISO 9001:2015 facility in India: production-ready and Built in India for Make in India programmes. PAPIS onboard passenger announcement and information hardware is built to EN 50155. Production includes in-circuit and functional test, AOI and X-ray inspection, and thermal cycling. The team can discuss your EN 50155 requirements, including temperature class, supply voltage, mounting location and documentation, and build to your specification.
Related
Passenger announcement and information system for metro trainsets, with hardware built to EN 50155.
See PAPIS product details →Onboard and station IP surveillance with centralised video management and vandal-resistant cameras for rolling stock and stations.
See IP CCTV product details →Remote diagnostic and performance monitoring for locomotive and rolling stock fleets, with edge data acquisition and predictive maintenance alerts.
See RDPMS product details →FAQ
EN 50155 is the European standard for electronic equipment used on rolling stock. It sets requirements for operating conditions, design, documentation and testing so that onboard electronics work reliably on railway vehicles. The current edition is EN 50155:2021, and IEC 60571 is the closely aligned international standard.
Since the 2017 edition there are six classes: OT1 (−25 to +55 °C), OT2 (−40 to +55 °C), OT3 (−25 to +70 °C), OT4 (−40 to +70 °C), OT5 (−25 to +85 °C) and OT6 (−40 to +85 °C). OT3 applies unless the specification states otherwise.
EN 50155 refers to EN 61373 for shock and vibration testing of rolling-stock equipment and to EN 50121-3-2 for the electromagnetic compatibility of rolling-stock apparatus. A complete EN 50155 test programme normally includes evidence against both.
Ask for the type test report against the edition you specify, the temperature and supply interruption classes tested, EN 61373 and EN 50121-3-2 results for the right mounting location, routine test records for delivered units, and lifecycle support commitments. A test report for the exact product configuration is stronger evidence than a datasheet statement.
PAPIS onboard hardware from Envision TechWorks is built to EN 50155. For other onboard electronics, the team can discuss your EN 50155 requirements, including temperature class, supply voltage, mounting location and documentation, and build to your specification in an ISO 9001:2015 facility in India. Use Talk to Us on the Contact page to share your requirements.
Share your temperature class, supply voltage, mounting location and documentation needs, and the team will discuss how to build to your specification, Built in India.