Victorian Railways N class
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| Type and origin | |
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| Power type | steam |
| Builder |
Newport Workshops North British Locomotive Company |
| Specifications | |
|---|---|
| Configuration: |
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| • Whyte | 2-8-2 |
| Gauge | 5 ft 3 in (1,600 mm) |
| Driver dia. | 55 in (1,397 mm) |
| Length | 67 ft 5 1⁄4 in (20.55 m) |
| Axle load | 13 long tons 17 cwt (31,000 lb or 14.1 t) |
| Adhesive weight | 53 long tons 2 cwt (118,900 lb or 54 t) |
| Total weight | 124 long tons 16 cwt (279,600 lb or 126.8 t) |
| Tender cap. | 6 long tons 0 cwt (13,400 lb or 6.1 t) coal or 1,500 imp gal (6,800 L; 1,800 US gal) oil, 4,700 imp gal (21,000 L; 5,600 US gal) water |
| Firebox: • Firegrate area |
31 sq ft (2.9 m2) |
| Boiler pressure | 175 psi (12.1 bar; 1.21 MPa) |
| Heating surface | 1,777 sq ft (165.1 m2) |
| Cylinders | 2 |
| Cylinder size | 20 in × 26 in (508 mm × 660 mm) |
| Performance figures | |
|---|---|
| Tractive effort | 28,650 lbf (127.4 kN) at 85% boiler pressure |
| Career | |
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| Number in class | 83 |
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 (1,600 mm) to 4 ft 8 1⁄2 in (1,435 mm) standard gauge.
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.
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. Large scale standardisation of Australia's broad gauge rail network did not get underway until 1995, nearly thirty years after the withdrawal of the N class.
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