The Kaimai Express long-distance passenger train was operated by Tranz Rail under the Tranz Scenic brand (originally by New Zealand Rail Limited under the InterCity Rail brand) between the North Island cities of Auckland and Tauranga via Hamilton. It used the Silver Fern railcars and operated from 9 December 1991 until 7 October 2001.
In 1928, when the East Coast Main Trunk Railway was completed to Taneatua, a passenger train commenced operating from Auckland on a slow (12-hour) schedule. Within a year this was upgraded to 10.5 hours and named the Taneatua Express. For much of its life, it ran only twice or thrice weekly.
In 1959 the express was replaced by a daily railcar service using 88 seater railcars: due to negligible traffic to Taneatua, it terminated at Te Puke. It did not last long, as the circuitous rail route struggled to compete with private cars, being withdrawn from 11 September 1967.
In 1980 Tauranga radio station Radio BoP started running an excursion train from Tauranga to Matamata and Rotorua via the new Kaimai Tunnel under the name Kaimai Express, using NZR locomotives and carriages from Steam Inc and Railway Enthusiasts Society. The excursions were repeated in 1981 and 1982.
In 1991, the Silver Fern railcars that operated between Wellington and Auckland were replaced by the locomotive-hauled Overlander, and they were transferred to new routes from Auckland, the Geyserland Express to Rotorua and the Kaimai Express to Tauranga. The latter train's name came from the Kaimai Tunnel through the Kaimai Ranges, opened on 12 September 1978. This gave a much faster and more direct route to the Bay of Plenty, substantially faster than the Taneatua Express and 88-seater railcars.