In addition to the provisions of subregulations (2) and (3), railway occurrences which result in injury, death or significant damage to property, including the environment, are to be recorded by the operator and reported immediately to the chief executive officer of the Regulator telephonically or by facsimile, followed by a report in writing (paper or electronic form) as soon as possible, but within twenty four hours after the occurrence, or as otherwise instructed by or agreed upon between the operator and the board.