Victorian Railways NA class

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Victorian Railways NA class
NA locomotive 12A at Belgrave on the Puffing Billy Railway 2005.
Type and origin Power type Steam Builder Baldwin Locomotive Works (2) VR Newport Workshops (15) Model BLW simple: 10-20 ¼ D BLW compound: 10-13/26 ¼ D Build date 1898–1915 Total produced 17
Specifications Configuration: ​  • Whyte 2-6-2T  • UIC 1′C1′ t Driver 2nd coupled axle Gauge 2 ft 6 in (762 mm) Driver dia. 36 in (0.91 m)[1] Length: ​  • Over couplers 30 ft 10 in (9.40 m) Height 10 ft 10 in (3.30 m) Adhesive weight 9 long tons 9 cwt 2 qr (21,220 lb or 9.63 t) Loco weight 35 long tons (36 t; 39 short tons) Fuel type Coal Fuel capacity 1.5 long tons (1,524.07 kg) Water cap. 780 US gal (2,952.62 L) Firebox: ​  • Type Round-top Boiler pressure 180 psi (1.24 MPa) Heating surface 524 sq ft (48.7 m2) Cylinders 2 Cylinder size 1, 3, 5-17: 13 in × 18 in (330 mm × 457 mm) High-pressure cylinder 2 & 4: 9+1⁄2 in × 18 in (241 mm × 457 mm) Low-pressure cylinder 2 & 4: 16 in × 18 in (406 mm × 457 mm)
Performance figures Tractive effort 12,170 lbf (54.1 kN) at 80% of boiler pressure
Career Preserved 3A, 6A, 7A, 8A, 12A, 14A Disposition 6 preserved, 11 scrapped

The Victorian Railways NA class is a 2-6-2 tank locomotive built for their four 2 ft 6 in (762 mm) gauge branch lines.

The Baldwin Locomotive Works in the United States supplied the first two 2-6-2 tank locomotives, as well as a range of spare parts. These two engines were numbered 1A and 2A and were both placed in service for construction of the Wangaratta to Whitfield line in the North East of Victoria in September 1898. The spare parts from the Baldwin Locomotive Works were used to construct locomotives 3A and 4A at Newport Workshops in 1900 for the Upper Ferntree Gully to Gembrook Line, with further examples of the class entering service up to the last, number 17A, in 1915. Engines 2 and 4 used Vauclain compound high- and low-pressure cylinders, while the rest of the class used simple expansion cylinders.

In 1920 parts were made for 2 more NAs—18A and 19A—but due to a downturn in traffic the order was cancelled, and the parts were used as spares on the other NAs. By the mid-1920s these small locomotives were not able to handle the increasing traffic, and two G class Garratt locomotives were purchased to supplement the fleet on the heavily patronized Walhalla and Beech Forest Lines.

Even with G41 and G42 in service the NAs were still the backbone of the VR Narrow Gauge Lines right up until the 1950s when they were progressively withdrawn from traffic between 1945 and 1960. 1A and 2A were withdrawn and scrapped in September 1929 due to being worn out. 4A was withdrawn in 1933 for the same reason and 16A was withdrawn in 1934 due to low use. They were both scrapped in September 1936.

The locomotives weigh 36.58 long tons (37.17 t; 40.97 short tons) and produce a tractive effort of 12,170 lbf (54.1 kN), allowing them to haul loads of 90 long tons (91 t; 100 short tons) up grades of 1 in 30 (3.33%). Numbers 6A, 7A, 8A, 12A, and 14A have been restored and operate on the Puffing Billy Railway, and No. 3 is also on the Puffing Billy Railway, currently plinthed in a dismantled state in the Lakeside Discovery Centre. The remaining locomotives have all been scrapped.

A 10+1⁄4 in (260 mm) gauge replica of a NA class locomotive was built in 1993 for use on the Isle of Mull Railway.^[2] The engine, named "Victoria", was built by the Mouse Boiler Works, using drawings provided by the Puffing Billy Railway. It operated on the Isle of Mull until the railway's closure in 2011, and is currently operating on the Rudyard Lake Steam Railway.