(a) General.— Except as provided in subsection (c) of this section, a railroad carrier and its officers and agents may not require or allow a train employee to remain or go on duty
(1) unless that employee has had at least 8 consecutive hours off duty during the prior 24 hours; or
(2) after that employee has been on duty for 12 consecutive hours, until that employee has had at least 10 consecutive hours off duty.
(b) Determining Time on Duty.— In determining under subsection (a) of this section the time a train employee is on or off duty, the following rules apply:
(1) Time on duty begins when the employee reports for duty and ends when the employee is finally released from duty.
(2) Time the employee is engaged in or connected with the movement of a train is time on duty.
(3) Time spent performing any other service for the railroad carrier during a 24-hour period in which the employee is engaged in or connected with the movement of a train is time on duty.
(4) Time spent in deadhead transportation to a duty assignment is time on duty, but time spent in deadhead transportation from a duty assignment to the place of final release is neither time on duty nor time off duty.
(5) An interim period available for rest at a place other than a designated terminal is time on duty.
(6) An interim period available for less than 4 hours rest at a designated terminal is time on duty.
(7) An interim period available for at least 4 hours rest at a place with suitable facilities for food and lodging is not time on duty when the employee is prevented from getting to the employees designated terminal by any of the following:
(A) a casualty.
(B) a track obstruction.
(C) an act of God.
(D) a derailment or major equipment failure resulting from a cause that was unknown and unforeseeable to the railroad carrier or its officer or agent in charge of that employee when that employee left the designated terminal.
