Columbia subject headings:
Fatigue--Research.
Railroad accidents--United States--Prevention.
Railroads--Employees--Health and hygiene--United States.
Railroads--Employees--Workload.
Railroads--United States--Safety measures.
Harvard subject headings:
Fatigue--Research.
Railroad accidents--United States--Prevention.
Railroads--Employees--Health and hygiene--United States.
Railroads--Employees--Workload.
Railroads--United States--Safety measures
Princeton subject headings:
Fatigue--Research.
Railroad accidents--United States--Prevention.
Railroads--Employees--Health and hygiene--United States.
Railroads--Employees--Workload.
Railroads--United States--Safety measures.