Tasmanian Government Railways Y class

Class of 8 Australian Bo-Bo diesel-electric locomotives

Tasmanian Government Railways Y class
TGR Y Class.jpg
 • UIC Bo-Bo
Gauge 1,067 mm (3 ft 6 in)
Wheel diameter 3 ft 0+12 in (0.927 m)
Minimum curve 250 ft (76.200 m)
Wheelbase 23 ft 10 in (7.264 m) total, 8 ft (2.438 m) bogie
Length 44 ft 9 in (13.640 m) over buffers, 41 ft 7 in (12.675 m) over headstocks
Width 8 ft 10+12 in (2.705 m)
Height 12 ft 2+12 in (3.721 m)
Axle load 14.5 long tons (14.7 t; 16.2 short tons)
Loco weight 58 long tons (59 t; 65 short tons)
Fuel type Diesel
Fuel capacity 500 imp gal (2,273.045 L)
Lubricant cap. 95 imp gal (431.879 L)
Prime mover English Electric 6SRKT Mk II (Y1-Y6)
English Electric 6SRKT Mk III (Y7-Y8)
RPM range 850rpm max
Engine type four stroke, four valves per cylinder
Aspiration turbocharged
Traction motors English Electric 537
Cylinders Inline 6
Cylinder size 10 in × 12 in (254 mm × 305 mm)
MU working 90V, nine notch electro-magnetic control
Loco brake straight air, proportional control
Train brakes Vacuum (Y1 & Y5
later converted to air)
Performance figures
Maximum speed 45 miles per hour (72 km/h)
Power output 825 hp (620 kW) gross, 750 hp (560 kW) net
Tractive effort 34,000 lbf (151.2 kN) at 6 mph (10 km/h)

The Y class was a class of diesel locomotives built by the Tasmanian Government Railways between 1961 and 1971.


The Y class were designed by English Electric and constructed by the Tasmanian Government Railways’ Inveresk Workshops. Eight were built as mainline freight and passenger locomotives between 1961 and 1971.[1]

Following the success of the X class, the Tasmanian Government Railways decided to order additional diesel locomotives.

English Electric submitted plans that were quite similar to the Jamaican Railways 81 class, South Australian Railways 800 class and Midland Railways of Western Australia F class but with a small power increase. They were slightly larger and more powerful than the X class.[1] They had a similar layout to the X class, a long hood unit with the cab at one end.

Construction began at the TGR’s Inveresk Workshops in 1961, and three of the planned eight were completed relatively quickly. However, construction of the other five was slow, with the last not being delivered until 1971, by which time the design had become dated.

Technical details[edit]

The Y class were fitted with an English Electric 6SRKT Mark II (Mark III on last two) in-line six turbocharged diesel engine. They have a Bo-Bo wheel arrangement and end-platforms, making them visually different from the X class.[1]

In line with standard TGR practice of the time, they were fitted with hook-and-link couplers and vacuum train brakes (air on locomotive). With a light tractive weight of only 58 tonnes, a reasonably powerful engine of 825 horsepower (615 kW) and a fairly basic bogie design, gaining traction on long uphill grades was found to be difficult. They were noted to have a tendency to wheel-slip badly. Nevertheless, they were considered successful.

Later years[edit]

In March 1978 the Y class were included in the transfer of the Tasmanian Government Railways to Australian National. With the new transfer of twenty 830 class locomotives from South Australia and later purchase of ZB class and ZC class locomotives from Queensland Rail, the Y class were made redundant.

In 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. Two also received air train brakes in 1985,[2] with the others withdrawn following the cessation of vacuum braked services in 1988. Some of these have been preserved.[3]

One was rebuilt in 2001 as a driving van for use on Railton to Devonport cement trains.[4] Two members of the class remain in regular service with TasRail, renumbered as the 2150 class since 1998.

Status table[edit]

See also[edit]