Summary: GAO discussed railroad accidents and engineer work schedules, focusing on whether: (1) railroads complied with the Hours of Service Act; (2) safety would be improved if the maximum number of hours per shift were shortened; and (3) other work schedule factors affect safety. GAO noted that: (1) the four railroads reviewed complied with the provisions of the Hours of Service Act and, 99.4 percent of the time, engineers were given at least 10 hours off duty following a work period of 12 or more hours; (2) it found no instances where an engineer received less than 8 hours off duty in any 24-hour period; (3) over 95 percent of human-factor-caused accidents in fiscal years 1989 and 1990 occurred before an engineer worked 10 hours in a shift and the highest accident frequencies appeared in the second through the sixth hours of the shift; (4) the four railroads estimated that about 83 percent of the engineers' work periods were no more than 10 hours long and that over 60 percent were no more than 8 hours long; (5) start time variability may increase fatigue for engineers, even if a worker receives time to rest following a work period; and (6) reducing the maximum number of hours allowed per shift from 12 to 10 has the potential for increasing schedule variability for those who regularly work such hours, which might actually contribute to increased fatigue and negatively affect performance.