(a) In addition to the inspections re-quired by § 213.233, each track owner shall conduct internal rail inspections sufficient to maintain service failure rates per rail inspection segment in ac-cordance with this paragraph (a) for a 12-month period, as determined by the track owner and calculated within 45 days of the end of the period. These rates shall not include service failures that occur in rail that has been re-placed through rail relay since the time of the service failure. Rail used to repair a service failure defect is not considered relayed rail. The service failure rates shall not exceed—