Y class
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In the late 1950s, The Tasmanian Government Railways (T.G.R.), after noticing the success of the 1952-vintage X class main-line diesel-electric locomotives, were keen to add others of the type to their fleet.
A repeat order of 'X' class engines may have been considered, but was quickly discarded (see TGR X class. After trying several manufacturers, they settled on English Electric (E.E.), the same company which had built the 'X' class engines. As a result, the plans E.E. submitted were quite similar to, and essentially a development of, the 'X' class, but slightly larger and more powerful.
When built, these engines were designated Y Class. Design-wise they are similar to the 'X' class - a long, hood unit with the cab at one end.
Construction started in the T.G.R. Inveresk workshops in 1961, and three of the planned eight were completed relatively quickly. However, construction of the other six was a drawn-out affair, with the last not being delivered until 1972, by which time the design was obsolete.
They are fitted with a E.E. 6SRKT in-line six turbocharged diesel engine (which was also fitted in the 'X' class locomotives), but producing 825 horsepower at 850 rpm as compared to the 'X' class 660 hp at 750 rpm. They have a Bo-Bo wheel arrangement and end-platforms, making them visually similar to but at the same time quite different to the older 'X' class engines. It is easy to confuse the two classes from a distance.
Like all T.G.R. rolling stock of the time, they were fitted with hook couplers and vacuum brakes.
With a light tractive weight of only 58 tonnes (one tonne heavier than the 'X' class), and a reasonably powerful engine of 825 horsepower, gaining traction on long uphill grades was found to be difficult. They have a tendency to wheel-slip badly. Nevertheless they were considered successful.
When the T.G.R. was overtaken by Australian National (A.N.) in 1978, the decision was made to import a batch of second-hand '830' class Bo-Bo diesel engines from South Australia, and some 2,000-hp G.E.C. diesels from Queensland, rapidly making the 'X' and 'Y' class engines obsolete. Nevertheless, throughout the late 1970s and early 1980s all members of the 'Y' class were retrofitted with stronger automatic couplers, which had by then become standard equipment. Some also received air-brakes, but those which retained their vacuum brakes were decommissioned in the late 1980s, coinciding with the eradication of their older 'X' class cousins. Some of these engines made their way into preservation societies.
The three members of the class which received air-brakes were retained by A.N., and later by Pacific National, as shunters and light-traffic engines.
In mid-2001 one of the survivors was rebuilt at Launceston. Its engine, generator, gearbox, driving controls and other traction equipment was removed, and the body weighted down with concrete. In this form the engine in question used a a 'dummy driving trailer' on the Railton-Devonport cement shuttle, where the driver in the former 'Y' class engine at the head of the train controls the motive power engine at the rear by means of remote controls. The other two surviving engines are in use as shunters at Boyer and Hobart, and are largely unmodified.
