The Wairarapa Mail was a passenger train operated by the New Zealand Railways Department (NZR) between Wellington and Woodville, continuing on to Palmerston North as a mixed train. It ran from 1909 until 1948 and its route included the famous and arduous Rimutaka Incline.
From the 1897 completion of the Wairarapa Line until 1908, the route through the Wairarapa was NZR's primary means of accessing Wellington as the western line through the Kapiti Coast and Horowhenua was privately owned by the Wellington and Manawatu Railway Company. The Napier Express passenger train operated from Napier to Wellington via the Wairarapa, but on 7 December 1908, the Wellington and Manawatu Railway was purchased, and in early 1909, the Napier Express was diverted to the quicker western route. Accordingly, the Wairarapa Mail was introduced to provide Wairarapa residents with connections to Wellington, Manawatu, and the Hawkes Bay.
After the WMR was acquired, most of NZR's long-distance trains used the WMR's Thorndon station as their Wellington terminus. The Wairarapa Mail was the only long-distance train to run out of NZR's Lambton Quay station, which primarily served commuter traffic from the Hutt Valley. Between the Hutt Valley and the Wairarapa, the train had to travel over the Rimutaka Incline over the Rimutaka Range, and at its terminus in Woodville, its carriages were attached to a slow mixed train from Dannevirke that continued through the Manawatu Gorge to terminate in Palmerston North. Passengers could also connect with the northbound Napier Express in Woodville.