NZR RM Class (88 Seater) - Operation

Operation

From almost the beginning they faced mechanical problems, with cooling being the primary issue. The engines had been designed for Italian naval boats and were unsuitable for the conditions. Although modifications were made they continued to have a reputation for unreliability throughout their career, frequently having to run with one motor isolated.

Unfortunately for NZR, the 1950s was a period of increased prosperity and saw massive increases in the numbers of private motorcars, along with improvements to roading such as tarsealing the main highways, and construction of the Auckland Harbour Bridge. These meant dramatic falls in passenger numbers, and in 1967-68 all railcar services from Auckland were cut except for the service to New Plymouth. This was cut back to operate between New Plymouth and Taumarunui in the early 1970s, with passengers making connections to North Island Main Trunk trains. All cancelled trains were replaced by New Zealand Railways Road Services buses.

Although the remaining services were to areas not well served by road, the mechanical condition of the 88-seaters meant that by the mid 1970s replacement was becoming urgent. It was decided to refurbish 14 of them, remove their engines and drivers' cabs, and convert them to what was known as AC class unpowered carriages. These were painted green and came to be known as 'grassgrubs'. They ran on the New Plymouth to Taumarunui, a newly reintroduced Napier to Gisborne service, Wellington to Palmerston North via the Wairarapa, Picton to Christchurch, and Christchurch to Greymouth services. The final run of an 88-seater railcar was in 1978 from Greymouth to Christchurch. The last trip came to an ignominious end when an engine failure and fire meant that passengers had to be taken onwards from Otira by bus.

The 'grassgrubs' were ill-fated. Their drawgear and bodies were not designed to be locomotive-hauled and they quickly wore out. By 1985 they had been withdrawn from service due to metal fatigue. Most of the passenger runs were continued after their demise, but the New Plymouth-Taumarunui service ended in 1983 (having already had its rolling stock replaced by 56 ft cars), and by the late 1980s the Wellington-Wairarapa service was abbreviated to terminate in Masterton as patronage on the Masterton - Palmerston North section was often fewer than 20 passengers per trip, due to improved highways and bus services. The AC class vehicles were replaced by NZR 56-foot carriages on the remaining Wellington-Napier, Picton-Christchurch, Wairarapa and Christchurch-Greymouth services.