 They had replaced the steam-hauled mixed trains and Wairarapa class railcars in 1955, when the Rimutaka Tunnel opened and the line became the first fully dieselised line in New Zealand.The Wairarapa Mail carriage train ran between Wellington and Woodville until 1948.In 1964, the demand between Masterton and Wellington was exceeding the capacity of the 88-seater railcars, with a capacity of 176 with two railcars.