Vibration syndrome in railway track maintenance workers.

An inquiry was sent to all railway maintenance workers in three railway districts in Finland and hand-arm vibration was measured on the handlebars of tools used by maintenance workers. The study group included 252 (82%) subjects, whose mean age was 41 years and who had worked in track maintenance for 14 years (SD 9). In Finland there are over 600 railway maintenance workers who use vibrating tools. The frequency-weighted acceleration of hand-arm vibration was calculated according to the ISO 5349 standard. Hand-held tamping machines had caused most of the vibration exposure, and aw4h was 10.6 m/s2 measured on the handlebar of tamping machine, but many workers also used other vibrating tools. The annual vibration level was 2.5 m/s2 when the use of all vibrating tools and the exposure time was taken into account. In the questionnaire the prevalence of vibration-induced white finger (VWF) was 14% in the entire material, and the prevalence of VWF increased significantly with the total duration of the maintenance work. In addition, 39% of the subjects had suffered numbness of the hands, and the prevalence of hand numbness also increased significantly with the total duration of maintenance work. According to the measurements of vibration and the prevalence of hand symptoms the present investigation indicates vibration syndrome as being related to railway track maintenance work. In the exposure group, where tamping machines mainly were used and exposure to other vibration was small, the prevalence of VWF was also significantly higher, but the prevalence of hand numbness insignificant compared with the control group. In this study vascular and nerve hand symptoms were considered to cause serious trouble in work by 4-11% of the maintenance workers.