NZR RM class (Leyland diesel)
The NZR RM class Leyland diesel railbus was the first diesel-powered vehicle to enter revenue service on New Zealand's national rail network. Two railbuses 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. Although sometimes considered to be railcars, their small size means that they more closely suit the definition of a railbus. They operated primarily on the Midland Line and the Greymouth-Hokitika portion of the Ross Branch.
These railbuses should not be confused with the Leyland experimental petrol railcar of 1925.
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History
The New Zealand Railways Department (NZR) had been looking for an economic means of handling 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. 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 tiny railbus. When the design proved to work, 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 25 feet long, and weighed nearly 8 tons. Power was provided by a Leyland 8.6-litre diesel engine that could produce up to 95 hp and propel the railbus at speeds of up to 50 mph. Up to 19 passengers could be carried, though a full load 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.
In service
Although they were only meant to be a temporary solution, the authorities who devised their schedule expected a lot from them. Their 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 2.20am departure from Christchurch, arriving in Greymouth at 6.40am and Hokitika at 7.55am, soon changed to 7.45am. Two local services were operated: a morning trip to Reefton (cut back to Greymouth in August 1938) and an afternoon trip to Greymouth. The return service left Hokitika at 4.25pm, called at Greymouth at 5.42pm, and reached Christchurch at 10.23pm.
The service between Greymouth and Christchurch was almost two and a half hours quicker than the locomotive-hauled passenger trains of the time. The railcars initially covered 526 miles a day, reducing to 434 miles when the Reefton service was cut back to Greymouth.
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. In 1941 more Vulcans arrived, replacing the Leylands, and in 1942 the Leylands were dismantled at the Addington Workshops in Christchurch.
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 (they could accommodate 49 passengers) and were designed especially to run over the steep Rimutaka Incline. They ran until the closure of the incline in 1955.
External link
Reference
- Leitch, David, and Scott, Brian; Exploring New Zealand's Ghost Railways, Grantham House, 1998 revised edition
