The N class was a branch line steam locomotive that ran on Victorian Railways from 1925 to 1966. A development of the successful K Class 2-8-0, it was the first VR locomotive class designed for possible conversion from 5 ft 3 in (1600 mm) broad gauge to 4 ft 8½ in (1435 mm) standard gauge.
History[]
In 1923, in response to the recommendations made by the 1921 Royal Commission on the matter of uniform railway gauge, VR announced a policy that all new locomotive designs were to be capable of conversion from broad to standard gauge. The rationale was that the task of converting VR from broad to standard gauge at a future date would be far easier to achieve if the existing locomotives and rolling stock could be easily modified for standard gauge operation, rather than requiring expensive re-engineering or replacement.
The K class 2-8-0 built by VR in 1922-23 was a success, but with a firebox mounted between frames engineered for broad gauge operation only, it was not readily gauge-convertible. Thus when additional branch line locomotives were required, the VR produced a 2-8-2 'Mikado' variant of the K, the first 2-8-2 tender engine in Australia. It retained the same wheels, cylinders, motion, and much of the frame of the K, but featured a longer boiler with a wider, larger grate, mounted above the frames and supported by a trailing truck. This enabled possible gauge conversion without radical re-engineering of the frames and grate.
A second series of N Class locomotives were produced in 1930 and a third series in 1949 as part of "Operation Phoenix", said third series evolving the N Class design by adding thermic siphons, combustion chambers, boxpok wheels and smoke deflectors.
10 of the second series N Class were sold to South Australia as the SAR 750 Class, which were unpopular with crews due to crammed cabspace, relative to their locomotives.
Despite these design features, no N class locomotive ever ran on standard gauge. By the time the standard gauge Albury to Melbourne mainline opened alongside the existing broad gauge line in 1962, steam locomotives were rapidly being withdrawn from service.
Preservation[]
Despite the large number of N Class locomotives built, very few were preserved.
N 432, as preserved at the ARHS museum
None of the first series N Class survived, although a project is underway to convert a K Class to a new 1st series N Class, only one of the second series N Class survive in South Australia as SAR 752 (ex. VR N 477) as a static exhibit in South Australia and only one of the third series N Class survives, N 432, at the ARHS Museum in North Williamstown as a static exhibit, which is also notable for being the last steam locomotive to be built by Newport Workshops.
Specifications[]
The N Class weighs 126.7 tonnes with an axle load of 14.1 tonnes. The engine has a boiler pressure of 175 psi and is capable of a tractive effort of 28,650 lbf. The firebox possesses a grate area of 31 square feet (2.9 m^2).The N Class has 2 cylinders with a 20 inch bore by a 26 inch stroke (508 x 660 mm). The driving wheels are 55 inches (1.4 meters) in diameter.
The tender is capable of holding 6 tons of coal/1500 gallons of oil (6800 litres) and 4700 gallons of water (21,400 litres).
Trivia[]
- Large scale standardization of Australia's broad gauge rail network did not get underway until 1995, nearly thirty years after the withdrawal of the N class.
- The N Class was the first design to be built with gauge conversion in mind
Gallery[]
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