NZR RM class (Leyland diesel)

The NZR RM class Leyland diesel railcar or Midland railcar was the first diesel-powered vehicle to enter revenue service on New Zealand's national rail network.^[1] Two were built, RM 20 and RM 21, and they commenced service in August 1936 as temporary short-use vehicles that would operate until better, larger rolling stock became available. Due to their diminutive and lightweight design, they are sometimes called "railbuses" rather than railcars. They operated primarily on the Midland Line and the Greymouth-Hokitika portion of the Ross Branch.

These railcars should not be confused with the Leyland experimental petrol railcar of 1925.

History

The New Zealand Railways Department (NZR) had been looking for an economic means of handling regional and rural passenger traffic for over two decades. Branch lines in rural New Zealand were typically operated by mixed trains that carried both passengers and goods, and their schedules were usually slow due to the loading and unloading of freight that occurred during the journey. This slowness made them unpopular with travellers, but insufficient demand existed to justify a dedicated passenger service. Secondary main lines in regional districts often had their own passenger trains, but these were often uneconomic, especially as car ownership and bus competition rose in the 1920s and 1930s. Thus, NZR investigated railcars as an alternate means of providing an attractive passenger service without the expenditure and costs associated with a locomotive-hauled carriage train.

The first experiment with railcars took place in 1912 with a MacEwan-Pratt petrol railcar, and while it was not a success, further research and development was undertaken in the following years. By 1936, no design had proven successful enough to warrant construction of a whole class, though an Edison battery-electric railcar built in 1926 had proved efficient and popular until it was destroyed by fire in 1934, and it might have been replaced with a similar railcar or expanded into a fleet if it were not for the financial constraints imposed at the time by the Great Depression.

In 1936, NZR and a newspaper company were looking into the development of a railcar to provide quick conveyance of both passengers and Christchurch Press newspapers from Christchurch to Westland: although long-term prospects for large railcars existed, a more immediate solution was required. For this experiment, NZR utilised a diesel-engined Leyland bus chassis to create a small railbus.^[1] Two were built at Hutt Workshops in Petone and entered revenue service in the South Island.

Technical specifications

The railbus used chassis of a Leyland Tiger bus, though once its body was constructed it did not look like a bus. It had four wheels, was 7.6 metres (25 ft) long, and weighed 8 tonnes (7.9 long tons; 8.8 short tons) unladen. Power was provided by a Leyland 8.6-litre (520 cu in) diesel engine that could produce up to 70 kW (94 hp) at 1,950 rpm and propel the railbus at speeds of up to 80 km/h (50 mph). Electric lighting and thermostatically controlled hot air radiators were both fitted Up to 19 passengers could be carried, though a full load of one tonne (0.98 long tons; 1.1 short tons) of newspapers meant only 13 could fit.

Initially, the two railcars had one technical difference: RM 20 was built with a four-speed manual gearbox, while RM 21 utilised a fluid torque converter. Not long after services began, RM 20 was also fitted with a fluid torque converter.^[1]

In service

Although they were only meant to be a temporary solution, the authorities who devised their schedule expected a lot from them. Before entering service, a trial run from Christchurch to Timaru in July 1936 demonstrated that the railcars could cover a distance of 160 km in 2 hours 8 minutes with the 80 km/h top speed successfully maintained.^[1] Their regular services were subsidised by the Christchurch Press and the first service of the day was timetabled to allow swift delivery of the morning edition of the paper. The first timetable came into effect on 3 August 1936 with a 2:20 am departure from Christchurch, arriving in Greymouth at 6:40 am and Hokitika at 7:55am, soon changed to 7:45 am. Two local return services were operated from Hokitika: a morning trip to Reefton (cut back to Greymouth by August 1938) and an afternoon trip to Greymouth. The return service left Hokitika at 4:25 pm, called at Greymouth at 5:42 pm, and reached Christchurch at 10:23 pm.^[2]

The service between Greymouth and Christchurch was almost two and a half hours quicker than the steam-hauled West Coast Express passenger trains of the time. The railcars initially covered 526 miles (847 km) a day, reducing to 434 miles (698 km) when the Reefton service was cut back to Greymouth.^[2]

The railcars' operating lives were mostly uneventful, but while operating the afternoon service to Greymouth on 18 January 1937, one was involved in a fatal accident north of Hokitika when it jumped off the rails at a level crossing near Arahura. 19 passengers and 3 railway employees were aboard; William Jeffries, a Hokitika auctioneer, was killed and twelve were injured. The derailment was caused by loose stones on the track that were scattered by a herd of cattle that had recently crossed the line; the front wheels left the rails while the rear ones did not, and the railcar in this condition travelled for 2.5 chains (50 m) as the driver unsuccessfully sought to stabilise and stop it. After this point, the rear wheels also left the rails as the front wheels dropped over the side of an embankment, and three chains (60 m) from the level crossing, the railcar had spun so that it faced in the direction opposite to that which it was travelling. The top of the railcar separated from the bottom, with the bottom half coming to rest fifteen feet (4.6 m) from the line down the side of the embankment while one end of the top half lay on the line.^[3] The railcar was subsequently repaired and returned to service.

Replacement

In 1940, the first Vulcan railcar was introduced into service. It took over the Monday, Wednesday, and Friday trips from the Leyland diesel railbuses on 28 October 1940, the Leylands continuing to operate on other days.^[2] In 1941 more Vulcans arrived, replacing the Leylands, and in 1942 the Leylands were dismantled at the Addington Workshops in Christchurch.^[1]

The Wairarapa railcars that entered service five weeks after the Leylands were similar, in that they were also based on the principle of a bus, but were much larger, accommodating 49 passengers, and were designed specifically to operate over the steep Rimutaka Incline. They ran until the closure of the incline in 1955.

References