Updated standard EN 50121, railway rolling stock and electromagnetic compatibility

driver's seat

It has been published the new edition of the standard IN 50121-3-2 "Railway applications, tramways, trolleybus and metro. Electromagnetic compatibility - Part 3-2: Rolling stock - Apparatus ". This recent update addresses the technical standard called from the harmonised standards IN 50155 "Railway applications, tramways, trolley bus applications — electronic equipment used on rolling stock "referred to by the European directive on the interoperability of the trans-European high speed rail system ’.
The new version, in force since may 2015, completely replaces the previous EN 50121-3-2 of 2006, that however will remain applicable until may 2018.
As has already happened for other updates in the railway sector, you have to expect that the manufacturers of these vehicles require the early implementation of the new rule before it becomes mandatory, given the time of completion of projects, the large number of components present and rather long lifetime of railway vehicles.

EMC News: appliances up to 6 GHz and new standards for measurement methods

EN 50121-3-2, concerning the electromagnetic compatibility, in the new version makes some substantial changes compared to the previous edition.
First emission and immunity measures extends to devices up to 6 GHz, taking into account, Like this, even telecommunications standards that use frequencies above 5 GHz, such as some variants of the standard WiFi. laptop on railway wagonThe application of this rule ensures, then, the devices commonly used by passengers on these media do not interfere or are not bothered by electrical and electronic systems aboard railway vehicles.

A further innovation is the reference standard for the preparation of the environments and systems of measurement in the laboratory carrying out these electromagnetic compatibility testing. Unlike when indicated in the previous version, that this was a reference to standard EN 55011 "Industrial Equipment, Scientific and medical (ISM) – Radio disturbance characteristics – Limits and methods of measurement ", in the new version reference is made to the standards of the Group EN 55016 "Specification for equipment and methods of measurement of radio disturbance characteristics and dell ’ immunity".
It then goes from ’ application of a rule of "niche", which concerns scientific equipment and measuring instruments, all ’ application of a rule more general and widespread, that covers among other things all consumer equipment.

A tendency to converge towards a unique standardization

The last amendment shows how a process of convergence towards a unified way to perform measurements in products belonging to different categories and scopes, accordingly, fall under different directives. In this way the regulations follow the technical evolution and costume in place, in which the same dominant technologies permeate various areas and, at the same time, see live increasingly distinct time scopes. For example, all commonly used tablet ’, Laptops and wireless technologies on trains, planes and yachts.

internalA similar process of convergence is occurring even in the military, for example, in the case of equipment of various kinds provided to law enforcement and military bodies. According to current European legislation these equipments are exempted from compliance with the same limitations and the same criteria to which are subject electronic devices for civil use; however, in order to avoid electromagnetic compatibility issues that otherwise would have occurred, in recent years, is often asked to certify also the equipment according to the standards of civilian equipment.
Inoltre l’applicazione degli standard di sicurezza civili in ambito militare afferma il principio secondo cui anche per il personale militare, like any other worker, la salute e la sicurezza devono essere tutelate da rischi non necessari.


  1. David

    This updated version of the EN50121-3-2 from 2006 to 2015. I take it this is only applicable to new models/equipment coming into the market now ?
    One would hope that anything already selling into the market complying to the 2006 level is ok. Otherwise it will be a headache for manufacturers and all we will be doing is testing our products to death with the continuous changes to standards and directives from the EU.



    1. Admin (Post author)

      Generally all the produced units coming to the market must comply with the new standards. There is an overlapping time in the range between four months to two years during which both the old and the new standard can be used; in this way there is a reasonable time for the verification of the compliance to the new standard and the modification of the product if necessary. It is usually not required a complete testing and therefore the cost is not too high.

      The case of EN50121-3-2 is slightly different because it is not a harmonized standard on its own, instead it is referenced by the harmonized standard EN 50155. Now the problem is that the reference is explicit to the 2000 version of EN50121-3-2, that is rather old.

      Our customers usually requested the testing according to the 2006 version and now they show interest for the 2015 version.
      It is mainly to remain ahead of the next changes and be sure to be compliant with the tenders technical specification.
      The EM immunity to frequencies in the 5 GHz range, now widely used in consumer electronics, is also a practical concern.


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