The EC directive on electromagnetic compatibility (EMC) was first agreed in 1989. Generic EMC standards appeared in the early 1990s. However, a transition period was implemented throughout the community from 1992 until December 1995, largely in order for product-specific standards to appear and also to allow time for industry to adapt to the change in legislation. At radio frequencies, the railway industry in the United Kingdom had made use of a standard produced by the Railway Industry Association (RIA) Committee 18 prior to the European Commission (EC) directive. This committee has made a substantial contribution to the Cenelec (European Committee for Electrotechnical Standardization) working groups which have produced five railway EMC pre-standards (ENV50121-1 to ENV50121-5) which were agreed in December 1995. There is a need in the period of two to three years from this date to develop the pre-standards and trial them with a view to turning them into full standards. Compliance with the EMC directive must be via the technical construction file route until the ENVs are converted to ENs and published in the official journal. This paper explains the standards used in the United Kingdom for EMC on railways prior to the EC directive and it describes the progress made towards developing the European pre-standards covering ‘A description of railway EMC’(ENV50121-1), ‘A method of measurement and cartography’ (ENV50121-2), ‘Railway vehicles’ (ENV50121-3), ‘Railway signalling’ (ENV50121-4) and ‘Fixed power installations’ (ENV50121-5). The paper shows the derivation of the major parts of the standards, including details of railway test data used to determine limits. The paper concludes by showing the implications for the railway industry in implementation and the expected progress in the next five years.
The Accuracy of Dead Reckoning in the Air