A series of measurements has been carried out on trains in order to determine the comfort level for crew and passengers. Different trains and varying rail sections were evaluated at train speeds of 120 to 180 km/h. The main problem area is the comfort of standing persons and especially the crew. The measurements were carried out sampling the time varying signal from an x-y-z transducer mounted directly on the floor. The measurements were carried out from 0.1 to 100 Hz and stored directly onto a PC hard disk for later processing. The processing was carried out according to ISO 2631 and ISO 8041. Having the raw data signal available enables one to process the data using different time constants and weighting curves as well as root-mean-square and fourth-power values. A linear integrated value of the entire duration of a trip has little correlation with the perceived comfort. A subjective evaluation using a group of standing people judging their comfort level, on a 5-stage scale from very comfortable to very uncomfortable, shows good agreement with the running rms acceleration level using a 10-s time constant. The lateral exposure level in the Y direction (90(degrees) to direction of travel) for a comfortable ride was 0.4 m/s[sup 2].