Tasmanian Government 4-8-2 Locomotives in Australia

Class H (Locobase 8579)

Data from [], [], and [], all accessed 14 July 2007.

These small Mountains (Hills?) were works #5949-5956. They had cast-steel SCOA-P drivers and roller bearings on every axle including the four under the tender, the main (connecting) rod, and the side (coupling) rods. As delivered, the superheater measured 372 sq ft, but the diagram prepared by the Tasmanian's chief mechanical engineer H Townsend showed substantially less area and slightly more firebox area. Locobase adopted Townsend's numbers because they were taken from locomotives in service.

Class Q-original (Locobase 21251)

Data from TGR locomotive diagram L 12 at [], last accessed 13 March 2025.. See also "The Railways of Tasmania", Locomotive Magazine, Volume XXVIII [28] (14 October 1922), pp. 88-91 (15 November 1922), pp. 323-326; and (14 April 1923, p. 97.. (Thanks to Oz Pete (Peter Dunn) for his 13 March 2025 email correcting the valve gear. A review of Locobase 9559, which first appeared in 2008, led to the addition of this entry.)

As delivered, these "heavy goods" (freight) engines had somewhat small boilers with Belpaire fireboxes.Their Schmidt British-pattern superheaters dispensed with dampers (as many other designs had done) but had a "patent circulatory system. Its "neat arrangement" of the radial constant-lead valve gear actuated 9" (229 mm) inside-admission piston valves and drove the second coupled axle.

LM noted the class's "somewhat severe" operating environment: :[I]t abounds in continuous grades of 1 in 40 (2.5%), together with many curves of five chains interspersed only with 40 ft (12.2 m) straights." Locobase considers LM's judgement to be "somewhat" understated.

This class was supplied in several batches from several Australian builders throughout the country. Perry Engineering of Gawler, South Australia delivered the first 6 in 1922 (along with 4 R-class 4-6-2). The TGR turned to Walkers Engineering across the continent in Queensland for the next 3 in 1929. And Clyde Engineering of New South Wales finished off the class with 6 in the late 1930s and 4 more in 1940. Two of the latter were delivered in 1944 while parts for the last two were sent to the TGR, which assembled them in 1945.

According to the Tasmanian Transport Museum's Q5 exhibit page ([], last accessed 6 September 2008), these locomotives "...the class handled the majority of mainline goods trains around the state."

Locobase notices that not even the Vulcan H class had cylinders as large, nor did they have thermic syphons. TGR applied a signficant design change to the later Qs; see Locobase 9559.

Class Q-rebuilt-combustion chamber (Locobase 9559)

Data from TGR locomotive diagram L13 at [], last accessed 13 March 2025.(Thanks to Oz Pete (Peter Dunn) for his 13 March 2025 email correcting the valve gear.)

Locobase 21251 describes the TGR's Q class as delivered. When they debuted in 1922, these "heavy goods" (freight) engines had somewhat small boilers with Belpaire fireboxes.

Over the next 20 years the TGR either built or modified the boilers and fireboses of at least fourteen in several respects. A combustion chamber reduced tube length by 31 1/2". Superheater counts remained the same but the update sacrificed 38 small tubes and reduced evaporative heating surface area in order to increase the direct heating surface area afforded by the combustion chamber and two Nicholson thermic syphons.

TGR retired the first Q (Q9) in 1956; Q4 and Q12 completed the withdrawls in 1963.

The last four saw their boilers set to 180 psi (12.4 bar).