49 CFR § 225.23 - Joint operations.
(b) In all cases involving joint operations, each railroad must report on Form FRA F 6180.55a the casualties to all persons on its train or other on-track equipment. Casualties to railroad employees must be reported by the employing railroad regardless of whether the employees were on or off duty. Casualties to all other persons not on trains or on-track equipment must be reported on Form FRA F 6180.55a by the railroad whose train or equipment is involved. Any person found unconscious or dead, if such condition arose from the operation of a railroad, on or adjacent to the premises or right-of-way of the railroad having track maintenance responsibility must be reported by that railroad on Form FRA F 6180.55a.
(c) In rail equipment accident/incident cases involving joint operations, the railroad responsible for carrying out repairs to, and maintenance of, the track on which the accident/incident occurred, and any other railroad directly involved in the accident/incident, each must report the accident/incident on Form FRA F 6180.54.