In the early 20th century, NZR began investigating railcar technology to provide profitable and efficient passenger services on regional routes and rural branch lines where carriage trains were not economic and "mixed" trains were undesirably slow. A number of experimental railcars and railbuses were developed:
The most successful of the experimental and early railcars was the Edison battery-electric railcar, which provided a popular twice-daily service on the Little River Branch line in Canterbury. It may have been expanded into a full fleet of railcars had the economic difficulties of the Great Depression not intervened, and it was destroyed by a depot fire in 1934 and not replaced.
Railcar classes
The first truly successful railcar classes to enter revenue service in New Zealand were the two that began operating in 1936, following the building of the Red Terror for the General Manager, Garnet Mackley, in 1934. More classes followed over the years, primarily to operate regional services. The various classes were:
The Silver Ferns were the only railcars to survive into the privatisation era of Tranz Rail and Toll Rail, and later re-nationalisation as KiwiRail. They were introduced to provide a premier service on the North Island Main Trunk between Wellington and Auckland, and after they were replaced by the Overlander locomotive-hauled carriage train in 1991, they were redeployed to operate the Geyserland Express between Auckland and Rotorua, Kaimai Express between Auckland and Tauranga, and Waikato Connection between Hamilton and Auckland. When those services were cancelled in 2001, the Silver Ferns were transferred to Auckland and operated suburban services for the Auckland Regional Transport Authority between Britomart and Pukekohe station. The Silver Ferns were then only used for special charter services and were withdrawn in 2019.
Speed records
The fastest speed officially achieved on New Zealand's railway network was attained by a Vulcan railcar. On a trial run on 25 October 1940, the speed of 125.5 km/h was achieved on a flat stretch of the Midland Line east of Springfield. In September 1938 Standard railcar RM 30 covered the 321 km between Napier and Wellington in 4 hours and 36 minutes running time. In 1967 RM 30 took a group of railway enthusiasts from Auckland to Wellington in 9 hours and 26 minutes. The Wairarapa railcars hold the fastest speeds for operations over the Rimutaka Incline. Passenger services were previously slow trains operated by the H class locomotives specially built to operate on the Fell mountain railway system employed on the Incline. The Wairarapa railcars were designed to operate unaided on the Incline, and as they were lighter and more nimble, they achieved speeds well in excess of any service operated by an H class.
Preservation
None of the experimental or early railcars survived to be preserved, but the Pleasant Point Museum and Railway operates a Model T Ford replica and possesses the unrestored body of one of the original Model T railcars. At least one member of all of the main railcar classes has been saved for preservation. For many years, it was feared that no 88-seater would be preserved, but the Pahiatua Railcar Society has successfully recovered one and is actively seeking to return it to operational condition. The same society is in possession of the sole surviving Wairarapa railcar and is restoring it to operational condition. Four of the nine Vulcan railcars are preserved, one by the Plains Vintage Railway and three by the Ferrymead Railway. Four of the six Standard railcars are also preserved, two by the Silver Stream Railway, one by the Pahiatua Railcar Society, and one by private interests in the Waikato stored at the Glenbrook Vintage Railway. All three Silver Ferns are currently withdrawn awaiting a decision about their future. One has been leased to Dunedin Railways for use on trips out of Dunedin.
