The New Plymouth Express was a passenger express train operated by the New Zealand Railways Department (NZR) between Wellington and New Plymouth. It ran from 1886 until 1955 and was sometimes known as the New Plymouth Mail due to the Railway Travelling Post Office carriages included in its consist. The Express was notable amongst NZR's provincial expresses as being both the first and, until the commencement of the Gisborne Express in 1942, the longest in distance travelled.