49 CFR § 214.331 - Definite train location.
(b) Each Class I or commuter railroad shall include in its on-track safety program for approval by FRA in accordance with § 214.307 of this part a schedule for phase-out of the use of definite train location to establish on-track safety.
(1) Such procedures were in use on January 15, 1997, or
(2) The number of trains operated on the subdivision does not exceed:
(i) Three during any nine-hour period in which roadway workers are on duty, and
(ii) Four during any twelve-hour period in which roadway workers are on duty.
(2) A definite train location list shall indicate all trains to be operated on the track for which the list is provided, during the time for which the list is effective.
(3) Trains not shown on the definite train location list shall not be operated on the track for which the list is provided, during the time for which the list is effective, until each roadway worker to whom the list has been issued has been notified of the train movement, has acknowledged the notification to the train dispatcher, and has canceled the list. A list thus canceled shall then be invalid for on-track safety.
(4) Definite train location shall not be used to establish on-track safety within the limits of a manual interlocking, or on track over which train movements are governed by a Traffic Control System or by a Manual Block System.
(5) Roadway workers using definite train location for on-track safety shall not foul a track within ten minutes before the earliest time that a train is due to depart the last station at which time is shown in approach to the roadway worker's location nor until that train has passed the location of the roadway worker.
(7) Each roadway worker who uses definite train location to establish on-track safety must be qualified on the relevant physical characteristics of the territory for which the train location information is provided.
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