Diesel Traction

The main-line diesel-electric (Fig. 11) was the answer, and the first diesels were introduced in the early 1950s, applying imported British and particularly U.S. technology and power equipment to Australian designs and mechanical specifications. Australian manufacture of traction motors and auxiliaries increasingly followed.[11]

11 Two GM1-class diesel-electric locomotives of Australian National Railways powering the Indian Pacific between Port Augusta and Port Pirie (photo courtesy Leon Oberg, Goulburn, New South Wales)

No other single development revolutionised the main-line railways so beneficially, so quickly and so universally as the diesel electric locomotive. While there were major economies from low cost distillate fuel, the diesel locomotive went much further than that. It worked longer, ran further and demanded much less attention than the two to three steam locomotives it displaced. It cost less per ton-km of traffic task and permitted substantial economies through smaller depots, workshops and labour forces, and the elimination of vast but little known watering and boiler repair infrastructures. The diesel engine had a finite power and the locomotive could not be worked at above rated output at all, or at slow speeds and maximum output for as long as a steam locomotive could (by operation at full throttle and long cut offs). But the diesel's superior starting performance (it being an all adhesive locomotive), its superior flexibility for freight and passenger duties, and its ability to operate in multiple unit under a single crew to match power with traffic demand, produced further economies from flexibility of operation. As a result, the complete 'railway towns' that had grown with and around the steam locomotive simply withered away.

In the workshops and locomotive factories the traditional 'in house' equipment (and many of the skills) of foundry, heavy machine shop and boiler shop were replaced by those of the carriage and wagon builder and his sub-contractors.

The Australian diesel-electric locomotives (Fig. 12) used American (Clyde-GM, Goodwin and later Comeng-AIco; GE in association with Goninan) and British power equipment (English Electric was the only widely used marque.) The mainline units had V12 and V16 diesel engines in power ranges from typically 750 to 1350 kW, all but the GM being 4 cycle engines; dc generators (with series-parallel control and automatic transition from the outset); and a variety of electro-magnetic contactor-type switchgear substantially derived from straight-electric practice. Power control principles followed Lemp's 1914 patent. From the earliest days, most diesels also had rheostatic electric (dynamic) brakes which effected major economies in train brake-block wear (especially when descending the Great Dividing Range in the Eastern States.) The near-universal Australian configuration was a 6-axle (Co-Co) unit on 18-22 t axles (1435 and 1600 mm gauges) and 15 t axles on the 1067 mm, lower on branch lines units in both cases (Fig. 12).

12 Early model Clyde-GM diesel electric locomotive QR 1400 class built in Australia for the Queensland Railways (photo courtesy Queensland Railways)

Australian Academy of Technological Sciences and Engineering