New South Wales D55 class locomotive
| Industry | Locomotive manufacturing |
|---|---|
| Headquarters | Australia |
| Products | Steam locomotives |
The D55 class comprises a fleet of 2-8-0 steam locomotives constructed by Clyde Engineering for use by the New South Wales Government Railways in Australia.
Construction
In 1916, Clyde Engineering was commissioned to produce 300 K class locomotives. Edward Lucy, the Chief Mechanical Engineer, introduced the Southern valve gear—a design uncommon outside the United States—making this the first NSWGR mainline locomotive to feature external valve gear. This advancement enhanced valve timing compared to the prior 460 class Standard Goods Engines.
The inaugural locomotive, initially designated K1353, began operation on 29 November 1918. However, prolonged testing delayed subsequent deliveries, resulting in the contract being scaled back to 120 units. By March 1925, all units were in service, each paired with large-capacity "Wampu" tenders. The last 30 locomotives incorporated self-cleaning smokeboxes and external bearings on their leading pony trucks. During World War II, the D55 class was evaluated for potential deployment as War Department engines in Iran and Iraq.
Operations
The 55 class mainly operated from depots at Enfield, Goulburn, Harden, Junee, and Cowra, primarily servicing the Illawarra and Main South routes. Their presence on the Main Western and Main Northern lines was infrequent.
In 1946, following coalfield disturbances after WWII, seventy locomotives were converted to oil firing. The 55 class was particularly suitable for this adaptation because no eccentrics were located near the firebox throatplate, facilitating installation of burners and associated piping. Their tenders were modified to include fuel tanks. Fuel oil was delivered into the firebox through steam jets controlled by the fireman. Initially, distillate was used as fuel, which was five times more expensive than coal; however, reduced servicing intervals were expected to balance these costs.
Subsequently, cheaper crude oil became available, prompting further modifications such as heating coils within tanks and pre-heating near burners to ensure effective atomisation. Ten additional conversions occurred in 1947 and another 54 in 1949. As the fuel crisis subsided, oil-fired locomotives were gradually withdrawn due to operational expenses that were four times higher than coal-fired counterparts; sixteen were reverted to coal firing while others were placed in storage. The final oil-burning unit, number 5591, was retired in February 1959.
A distinctive characteristic of these oil burners was a hinged chimney cover designed to shield boiler tubes from rapid cooling when fires were extinguished.
Although primarily freight engines, two locomotives underwent modifications with balanced wheels to operate the Cooma Mail route south of Goulburn. The last D55 class locomotive was retired from Enfield Locomotive Depot in June 1967, making this class the earliest among Standard Goods engines to be withdrawn.
Preservation
| Number | Builder | Year | Owner | Location | Status |
|---|---|---|---|---|---|
| 5595 | Clyde Engineering | 1924 | Transport Heritage NSW | Thirlmere | Static Display |