49 CFR 225.13: Late reports.

Whenever a railroad discovers that a report of an accident/incident, through mistake or otherwise, has been improperly omitted from or improperly reported on its regular monthly accident/incident report, a report covering this accident/incident together with a letter of explanation must be submitted immediately. Whenever a railroad receives a partially or fully completed Employee Statement Supplementing Railroad Accident Report (part II of Form FRA F 6180.78), in response to a Notice to Railroad Employee (part I of Form FRA F 6180.78) issued by the railroad and mailed or hand delivered to the employee, the railroad must promptly review that Supplement; based on that review, reassess the accuracy and validity of the railroad's Rail Equipment Accident/Incident Report and of any other reports and records required by this part concerning the same accident, including the Employee Human Factor Attachment; make all justified revisions to each of those reports and records; submit any amended reports to FRA; and submit a copy of any amended Rail Equipment Accident/Incident Report, Employee Human Factor Attachment, and Highway-Rail Grade Crossing Accident/Incident Report on the accident to the employee. A second notice under § 225.12 is not required for the employee. If an employee who was never sent a notice under § 225.12 for that accident is implicated in the revised Employee Human Factor Attachment, the railroad must follow the procedures of § 225.12(d).