The health effects of ELF-EMFs pose an intriguing unsolved problem in
epidemiology. Prompted by an earlier occupational study demonstrating
an excess mortality from malignancies of the haematopoietic and lympha
tic systems (abbreviated as MHLS, ICD-8: 200-209) among railway engine
drivers, exposure measurements in the driver's cabin were taken. Meas
urements of the alternating magnetic field strength (frequency 16.67 H
z) were made in a representative set of locomotives prevalent in Switz
erland in the 1950s and 1960s. Because of particular working condition
s of the railway engine driver, exposures may be estimated fairly reli
ably. Estimated yearly exposures amounted to 0.7 mT.d up to 9 mT.d dep
ending on the type of engine. The earlier finding of an elevated morta
lity from MHLS among Swiss railway engine drivers has to be seen in th
e light of these fairly high estimates for some engine types.