Electronic components in railway applications have to conform with rigid safety levels, often combined with the most rugged environmental requirements. Because of the danger to human life and high downtime costs, reliability must be predictable, regular maintenance must not be required, batteries are not allowed etc. Thus, only the highest quality in development and industrial production guarantees a reliable product for an operation period of 20 years and more.

EN 50155 in Development and Qualification

Development and therefore the supplier company must conform to ISO 9001. During the design phase the layout of the board and the choice of components critically influences the suitability for operation in extended temperature (Tx = -40 to +85°C), under shock, vibration, humidity and chemical influence. Conformal coating as well as high-voltage isolation is mandatory, components must conform to EN, CECC or IEC standards, must have a second source or must be used only in the specification range of the data sheet (which forbids temperature screening) – for example. Electronics must provide functions such as memory check, self test, watchdog, error output or re-start within a short time.Hardware and software design is carried out according to EN 50126, EN 50128 and EN 50129 when the application is safety-critical. The optimum board design also anticipates the quality of the software design and the quality in production and testing. This requires the usage of appropriate development tools for design and simulation. EDA tools should be directly coupled to the manufacturing data base.Testing prescribes type tests, routine tests and investigatory tests. Type tests include for example low temperature, dry heat, humid heat cycles, over-voltage, electromagnetic immunity, radiation, isolation, salt fog, shock and vibration etc.MEN maintains its own laboratory with a climatic cham-ber, Emc chamber and shaker for pre-qualification and cooperates with LGA (Landesgewerbeanstalt Nürnberg) to achieve official EN 50155 approval. Anticipation... Saying Goodbye – but not to safety... 4