Magnetic fields on British trains.

People on trains can be exposed to static and alternating magnetic fields which are higher than background levels in most homes and many workplaces. Quantification of such exposure may be of interest for epidemiological purposes but it is also important to ensure that exposure guidelines are complied with. This article describes the types of electric trains and trams in use in the UK and the results of measurements of static and alternating magnetic flux density. Many of the data have been supplied by the operators of the systems described. The measurements summarised in this article are indicative of the magnitudes of magnetic field exposures to be encountered on British trains, but without concomitant frequency information, they are not sufficient to allow demonstration of compliance with exposure standards.