49 C.F.R. § 270.401
As used in this subpart-
Contributing factor means a circumstance or condition that helps cause a result.
Fatigue means a complex state characterized by a lack of alertness and reduced mental and physical performance, often accompanied by drowsiness.
Fatigue-risk analysis means a railroad's analysis of its operations that:
(1) Identifies and evaluates the fatigue-related railroad safety hazards on its system(s); and
(2) Determines the degree of risk associated with each of those hazards.
FRMP means a Fatigue Risk Management Program.
FRMP plan means a Fatigue Risk Management Program plan.
Safety-related railroad employee means:
(1) A person subject to 49 U.S.C. 21103 , 21104 , or 21105 ;
(2) Another person involved in railroad operations not subject to 49 U.S.C. 21103 , 21104 , or 21105 ;
(3) A person who inspects, installs, repairs or maintains track, roadbed, signal and communication systems, and electric traction systems including a roadway worker or railroad bridge worker;
(4) A hazmat employee defined under 49 U.S.C. 5102(3) ;
(5) A person who inspects, repairs, or maintains locomotives, passenger cars, or freight cars; or
(6) An employee of any person who utilizes or performs significant railroad safety-related services, as described in § 270.103(d)(2) , if that employee performs a function identified in paragraphs (1) through (5) of this definition.
49 C.F.R. §270.401