 It is a diesel-hauled carriage service, introduced by the New Zealand Railways Department in 1964 after passenger demand between Masterton to Wellington exceeded the capacity of the diesel railcars then used.The service operates five times daily in each direction Monday to Friday, three peak and two off-peak, with an additional service each way on Friday nights and two services each way on weekends and public holidays.It stops at all stations from Masterton to Upper Hutt, then runs express along the Hutt Valley Line to Wellington, stopping only at Waterloo and Petone stations.