The R class is a 4-6-4 Hudson express passenger steam locomotive that ran on Australia's Victorian Railways (VR) from 1951 to 1974. A much-needed replacement for the 1907-era A2 class 4-6-0, their development and construction was repeatedly delayed due to financial constraints caused by the Great Depression and later the manpower and materials shortages of World War II and the immediate postwar period.
Orders eventually totalling 70 locomotives were placed with the North British Locomotive Company of Glasgow. Once initial teething problems were overcome, R class locomotives proved to be a success and their power and speed enabled faster timetabled services. However, they were almost immediately superseded by mainline diesel-electric and electric locomotives on the Victorian Railways from 1952 onwards. With successive orders of diesel-electric locomotives through the 1950s and 1960s gradually displacing them, all but seven of the class were withdrawn and scrapped.
Four of the remaining locomotives were later restored to operating condition between 1984 and 1998. These have seen use ranging from hauling special heritage train services through to substituting for modern diesel-electric locomotives on regular intercity rail services run by V/Line and West Coast Railway. Another surviving example, number R 704, was originally displayed at the Festival of Britain in 1951 and is now on permanent display at the Newport Railway Museum in Newport, Victoria.
History
Within a few years of the introduction of the A2 class 4-6-0 in 1907, it was clear that increasingly heavy train loads would require a more powerful locomotive on principal main lines. From as early as 1918, a series of drawings for potential 4-6-2 'Pacific' type locomotives began to emerge from the VR's Locomotive Design Section, some of which were ultimately developed into the 3 cylinder S class heavy Pacific of 1928. However, plans for a smaller 2 cylinder Pacific, with an axle load below 20 tons to allow operation across the VR mainline network, were put on hold during the 1930s. This was partly due to the decline in traffic and revenue due to the Great Depression, and partly due to the improved power outputs and efficiency from the A2 locomotives after the application of a series of smokebox design and draughting changes referred to as 'Modified Front End' in the mid-1930s.
By 1943 however, the situation had changed. There was a massive increase in traffic brought by the advent of World War II, and the A2s were by this point well past their prime. The VR Locomotive Design Section once again turned their attention to the proposed Pacific replacement. The addition of a mechanical stoker, the enlarging of the grate from for increased performance and the use of heavy bar-frame construction for increased durability significantly increased the projected weight of the locomotive. To keep the axle load to 19.5 tons, the design by 1944 had changed from a 4-6-2 'Pacific' to a 4-6-4 'Hudson' wheel arrangement.
Design features
The R class reflected an ongoing evolution of VR locomotive design and a response to the changing operational environment of the VR in the postwar era.
The R class adopted the bar frame construction of the H and S class express passenger locomotives, which had proven to be far more robust in coping with the VR's varying track quality than the fracture-prone plate frames of the A2.
The decision to install MB Type 1 mechanical stoker equipment (capable of feeding up to of coal per hour) on a locomotive with only a grate reflected improved postwar working conditions for locomotive firemen, the varying quality of postwar coal and the expectation of sustained high speed operation of the locomotive. The manually fired prewar VR S class Pacific, although capable of 2,300 drawbar horsepower (1,700 kW), was limited by the physical ability of the fireman to feed its grate and as such was reliant on coal with a high calorific value.
Online locomotive database steamlocomotive.com notes: "They showed an interesting blend of European, British, American, and Australian practice. The slotted pilot is Australian, the long sand dome American, the Belpaire firebox and cab British, and the mid-line smoke lifters ('elephant ears') European."
Other modern features included SKF roller bearings on all axles and the innovative, lightweight SCOA-P type driving wheels, which were specially developed for the R class by the Steel Company of Australia.
Production An order for 20 locomotives was placed with the VR's Newport Workshops in 1946, but remained unfulfilled for years, because shortages of steel and manpower saw other projects given precedence, such as the overhaul of badly run-down infrastructure and the building of extra X class goods locomotives.
By the late 1940s, the A2 class was at the end of its life, and new motive power was desperately required. Australian Federal Government restrictions on the availability of US dollars, designed to favour trade within the British Empire, precluded the VR from purchasing American diesel-electric locomotives. The VR broke with a long-standing policy of in-house steam locomotive construction and called for tenders to construct an additional 50 R class. The contract was awarded to North British Locomotive Company of Glasgow, Scotland on 21 September 1949. On 12 January 1950, the order was increased to 70, with the cancellation of the original order of 20 of the locomotives from VR's Newport Workshops. Parts manufactured for the Newport order were used to complete the North British-built locomotives.
Further delays were experienced after the locomotives began arriving in May 1951. Corrosion had already set in during their sea voyage from Scotland to Australia as deck cargo, and there were numerous manufacturing defects requiring rectification. R 703 was the first of the class in service, on 27 June 1951, and the last of the fleet, R 769, did not enter service until 23 September 1953.
Service life
Once the manufacturing defects and corrosion damage were corrected, the R class proved to be a fine locomotive in its intended role of express passenger service, and individual R class locomotives were soon running upwards of each per week. Dynamometer car testing showed they were capable of producing a maximum 1,840 drawbar horsepower () at , a significant improvement over the A2's at . They quickly took over virtually all mainline passenger services previously operated by the A2 and passenger timetables were revised to take advantage of their higher performance, with cuts to journey times as high as 60 minutes. Although of similar size to the X class 2-8-2 goods locomotive, the R's more modern design features such as larger volume smokebox and better valve events courtesy of larger diameter piston valves with long travel contributed to its significantly higher horsepower output than the 1,400 drawbar horsepower () output of the X class.
Features such as the mechanical stoker, smooth riding characteristics and large, comfortable cab also made them popular with crews.
The R's impressive debut was cut short by the introduction of the B class diesel electric locomotives from July 1952. By the end of 1953, the success of the B class saw the R class withdrawn from The Overland service to Adelaide and also VR's passenger service to Mildura. The Gippsland line, which was electrified to Traralgon by 1955, was the first line to see the complete withdrawal of the R class from service. On 18 May 1964, R 703 worked the last regular steam-hauled passenger train out of Melbourne, the 6:05pm Geelong service.
The Rs were pressed into secondary passenger and goods service, roles for which a Hudson with large diameter driving wheels was sometimes a less than ideal choice. There was little opportunity to exploit their high speed capability. Furthermore, their relatively low factor of adhesion (4.08) and lack of fully compensated springing, coupled with the tendency of locomotives to transfer weight to the rearmost wheels under high drawbar pull conditions (which in the case of the R meant a weight transfer from the driving wheels to the unpowered trailing truck) caused them to slip when starting heavy goods trains.
The R class is remembered by many for its role as power for the seasonal grain harvest. In times of a good harvest, virtually every available locomotive would be marshalled into service to shift wheat trains of over 1,000 tons from Victoria's Western district through to the ports for export. Double-headed R class locomotives, sometimes aided by a third R acting as banking engine at the rear, could be seen battling the 3 mile, 1 in 52 (1.92%) Warrenheip Bank out of Ballarat.
In the 1960s, as the railway preservation movement began to gather momentum, a small number of R class locomotives found a new role as power for excursion train services. In this role they were able to fulfill their intended role of high speed passenger travel, with speeds of over being recorded.
Modifications Alternate fuels Pulverised Brown Coal
R 707, which due to various defects had still not been put into service by 1954, was selected for modification for precipitated brown coal (PBC) operation in conjunction with trials of this fuel being undertaken with X class 'Mikado' X 32. Dynamometer car tests with R 707 showed the locomotive was able to develop approximately 1,590 drawbar horsepower () at , roughly equivalent to the 1,605 drawbar horsepower () generated by a conventional R class locomotive burning second grade Lithgow black coal. However, comparative tests also demonstrated that R 707 also achieved considerably higher efficiency, capable of consuming 1.5 tons less coal on the Melbourne to Bendigo round trip hauling a 350-ton trailing load, despite the lower calorific value of brown coal than the Lithgow coal. While the PBC locomotives performed well, the expense of installing storage and handling facilities became increasingly uneconomic with falling prices for fuel oil and the success of diesel-electric traction. The conversion had also reduced the water capacity of R 707's tender such that there was insufficient margin for delays or bad weather running on many routes, confining the locomotive to the shorter Melbourne to Geelong and Seymour lines. The experiments were discontinued and R 707 was converted back to black coal operation in 1957.Pulverised Brown Coal Fuel for Steam Locomotives Buckland, John L. Australian Railway Historical Society Bulletin, July 1972 pp. 145–161
Oil firing
R 719 and 748 were converted to oil-firing during the mid-1950s using oil tanks and burner equipment salvaged from the four scrapped S class steam locomotives. They performed very well and were favourites among crews for their clean, cinder-free running. The reduced maintenance associated with their oil-fired operation meant they also had the highest availability of any of the R class and as such recorded the highest mileages of any of the class. However, rising fuel oil costs and the ongoing dieselisation program on the VR precluded any further locomotives from being converted. R 743 was in the process of conversion to oil firing as part of a major overhaul in February 1957 when instructions were issued to halt the conversion program and was returned to service as a coal fired locomotive.
Big-end oil cap As of late 1961, three Bendigo-based engines still working passenger services between Bendigo and Swan Hill - R709, R727 and R752 - had the wooden plugs in their big-end lubrication caps removed and replaced with a steel plug, thus requiring crews to remove the whole cap to confirm sufficient oil was present in that part of the mechanism. This change was made due to recurring failures caused by a lack of oil, and the change prevented that; each of the three engines were recorded working over three thousand miles per month.
Demise