As well as working days, holidays may be defined. Although supported by Passenger, the TXC-PTI profile does not recommend using these as they can overlap with working days and therefore cause confusion. 

<ServicedOrganisation>
  <OrganisationCode>KSCH</OrganisationCode>
  <Name>Kent School Terms</Name>
  <Holidays>
    <DateRange>
      <StartDate>2021-04-02</StartDate>
      <EndDate>2021-04-18</EndDate>
    </DateRange>
  </Holidays>
</ServicedOrganisation>

Continue to the next article on Managing Journey Data: Days of Non Operation.