Data Analysis for Maintenance-of-Way Worker Fatigue
This report examines the relationship between accidents and incidents amongst U.S. maintenance-of-way (MOW) employees and their corresponding work schedules to determine if fatigue-related factors potentially contributed to the events. Ten U.S. railroads participated in the study by providing MOW data. Study methodology consisted of using a biomathematical fatigue model to review work schedules to determine if they exceeded thresholds of acceptability on 12 factors that are known to be related to impaired performance due to fatigue. Participating railroads provided 10-day schedules to facilitate modeling of fatigue prior to the accident or incident. Exceeding the fatigue risk threshold on any of the 12 factors indicates elevated risk due to fatigue accumulation and subsequent impairment of performance. Results indicate that portions of the work schedules exceeded fatigue risk threshold levels for almost all 12 factors measured and in some cases, there were multiple factors that contributed to exceeding the fatigue risk threshold. This understanding can inform efforts to optimize MOW worker schedules to reduce fatigue and related human performance errors. The results may also support changes to safety standards regarding regulations for MOW work/rest periods to be consistent with other railroad employee work/rest regulations.