A service has an operating period (not to be confused with an operating profile), which is a start date for that service and optionally an end date. 

<Service>
  ...
  <OperatingPeriod>
    <StartDate>2021-03-08</StartDate>
    <EndDate>2025-12-31</EndDate>
  </OperatingPeriod>
  ...
</Service>

If none of the dates in the working days defined for a serviced organisation fall within the service’s operating period, Passenger interprets this service’s journeys as not running.

Continue to the next article on Managing Journey Data: Bank Holidays.