Shortly after the nationalisation of the WMR line, the Napier Express was diverted in 1909 from the Wairarapa Line to run through the Manawatu Gorge and down the former WMR line to Wellington. Thereafter, the main passenger service to stop at Opaki was its replacement, the Wairarapa Mail. A new passenger-only service was provided from 1936 with the introduction of the Wairarapa-class railcars, which supplemented and later replaced the Wairarapa Mail in 1948. The Wairarapa railcars were in turn replaced after the opening of the Rimutaka Tunnel in 1955 by the twinset railcars. The railcar timetable for 1959 shows only one required stop at Opaki Monday to Saturday on a morning Woodville - Wellington service, with request stops only for all other services. During the period in which railcar services were provided through Opaki, locomotive-hauled carriage trains were occasionally provided when demand exceeded the capacity of the railcars.