PHYSICAL, MENTAL, EMOTIONAL, AND SUBJECTIVE WORKLOAD COMPONENTS IN TRAIN DRIVERS

This study, using 12 train drivers on a high speed track and 11 driver s on a mountain track, tried to differentiate between the physical, em otional, mental, and subjective workload components imposed on the dri vers during work. With the simultaneous recording and on-line analysis of heart rate and physical activity, the emotional component in terms of the so-called additional heart rate was separated from the physica l component. Mental workload was calculated by the heart rate variabil ity and by shifts in the T-wave amplitude of the ECG. Speed of the tra in, mode of driving, and stress of the situation were rated by two obs ervers who accompanied the drivers in the cabin. During speeds up to 1 00 km/h as compared to standstills no heart rate changes occurred, but with speeds from 100 km/h up to 200 km/h heart rate decreased indicat ing a monotony effect. However, heart rate variability, and T-wave amp litude indicated higher mental load during driving in most speed categ ories. Starting the train and coming to a halt showed greater emotiona l workload as compared to moving. Observer ratings of stress and subje ctive ratings of stress by the drivers revealed several discrepancies. Discrepancies were also seen between workload as indicated by the phy siological parameters, and corresponding stress ratings by the observe rs or by the drivers.