When the number of passengers increased steadily after the Second World War, the NZR tried to gain as many passengers as possible from the developing road traffic. To do this, the steam trains had to be replaced with more modern types of transportation and, above all, the mixed passenger and freight trains had to be replaced with a more modern form. The tender for a modern 88-seater railcar was won by the English Drewry Car Company, with Fiat supplying the engines. The vehicles, which were 32 meters long in total, each consisted of two car bodies that shared a common Jakobs bogie in the middle. In each half was a motor that delivered its power electrically to two axles.

Shortly after the delivery of the 35 vehicles, however, the first problems became apparent. When used on the mountainous routes on the North Island, overheating or problems with the electrical system were common. As a result, the vehicles often had to run with just one engine and were late. In addition, glowing soot particles caused embankment fires during operation under full load. These problems were not resolved until Fiat technicians traveled to New Zealand to investigate. This ultimately led to the engines being derated from 210 to 185 hp each and a possible second order of 15 units did not materialise.

Despite the derating, cracks in the crankshafts continued to occur. Thus, in 1967, the procurement of replacement engines for all vehicles was put out to tender. Due to government regulations, however, only new crankshafts could be ordered, which limited the remaining service life of the vehicles. The service of the railcars was soon discontinued on some connections and replaced by locomotive-hauled trains. From 1976 some examples were converted into unpowered passenger cars, repainted green and called “Grassgrubs”. In the same year, major maintenance work on the remaining railcars was suspended, so that they were all retired by 1978.