For initial operations it is required (Section 2 in OPS Rolling Stock & Section 6.4.3 in OMGPR, MRTA’s requirements [1]):
1) Trains shall be capable of carrying the maximum line loading of passengers forecast in accordance with relevant data available under normal passenger loading conditions (W3) within the stated service interval range;
2) During peak hours, headways shall not exceed 4 minutes;
3) Between the morning and evening peak hours, headways shall not exceed 6 minutes;
4) After the evening peak hours, the headways shall not exceed 7 minutes for at least 2 hours of operation; and
5) During other off peak hours, headways shall not exceed 8 minutes.