New South Wales 73 class locomotive

Walkers Limited
Industry	Locomotive manufacturing
Headquarters	Maryborough, Australia
Products	Diesel-hydraulic locomotives (73 class)

The 73 class diesel-hydraulic locomotives were constructed by Walkers Limited in Maryborough expressly for the New South Wales Department of Railways between 1970 and 1973. A total of 50 units were built, each equipped with a Caterpillar D379 V8 turbocharged engine producing a gross power output of 700 hp and capable of reaching speeds up to 40 mph. These locomotives utilize Voith transmissions paired with Gmeinder final drives and have an approximate weight of 49 long tons.

Designed mainly for shunting duties and light freight services, the class has experienced various operational statuses over time: currently, 15 remain active within industrial sectors including Invicta Sucrogen and Mackay Sugar, while several others are either preserved or kept in storage. The engineering focus was on delivering dependable and efficient performance for regional rail operations in New South Wales.

History

In October 1969, the New South Wales Department of Railways placed an order for 20 B-B configured shunting locomotives from Walkers Limited based in Maryborough. These units represent the only locomotives built in Queensland specifically for New South Wales railways.

Delivery

The initial locomotive was delivered in October 1970. Following the completion of this first batch, steam-powered shunting was completely phased out on the North Coast line, throughout Sydney's Metropolitan area, and at Goulburn. Subsequently, in July 1971, an extra 30 locomotives were commissioned, with the final unit arriving by March 1973, effectively ending all steam shunting activities within New South Wales.

In traffic

Although these locomotives were primarily acquired to perform shunting tasks, they were officially prohibited from mainline operation due to the absence of vigilance control systems. Despite this restriction, they regularly handled suburban trip workings and occasionally operated on mainlines when circumstances required.

A notable benefit of these diesel-hydraulic units compared to diesel-electric types was their capability to run through track sections submerged under as much as 300mm of water. For instance, during significant flooding near Bourke in March 1976, unit 7323 was actively engaged hauling freight and ballast between Nyngan and Bourke. Comparable flood-related operations took place at Menindee in 1976 and at Hexham in 1977.

Operating multiple units simultaneously was a frequent practice; during the Hexham flood event, triple-heading was documented. Additionally, some locomotives were outfitted with exhaust gas scrubber systems to support construction work on the Eastern Suburbs railway line during the 1970s.

Depot allocation

As recorded on 30 August 1977, the distribution of the fleet across depots reflected a broad presence throughout the network:

Depot	Allocation
Eveleigh	7301–7314, 7317, 7321, 7339–7345
Goulburn	7315, 7316
Cootamundra	7319
Junee	7320 (assigned to Albury)
Lithgow	7326
Orange	7322
Dubbo	7323, 7324
Parkes	7325
Broadmeadow	7327–7338
South Grafton	7318
Werris Creek	7346 (operating at West Tamworth), 7347
Yeerongpilly	7348–7350

Withdrawal

The phase-out of locomotive-hauled passenger services and the closing of yards led to the commencement of withdrawals in February 1987. By October 1991, only three units remained active within SRA FreightRail, including one that had been repainted in CountryLink colors for shunting duties at the XPT Service Centre.

Disposal of units began in 1990, initially with three locomotives sold to the Canberra Railway Museum, followed by four more transferred to the Manildra Group in 1991. Several locomotives were also sold to Queensland sugar cane enterprises for conversion to gauge. A significant number have been preserved.

Units 7301 and 7344 were registered on RailCorp's Heritage & Conservation Register; however, 7301 was dismantled in January 2014.

Preserved

The following locomotives are maintained by preservation groups:

7307 & 7321: Held by the Oberon Tarana Heritage Railway, featuring the Patrick Portlink red and yellow scheme
7320 & 7324: Privately owned and stored in Canberra
7329 & 7335: Part of the collection at the Dorrigo Steam Railway & Museum
7344: Under the ownership of Transport Heritage NSW, previously managed by 3801 Limited (now East Coast Heritage Rail) until 2017; since December 2018, housed at the Rail Motor Society’s Paterson Depot. In 2020, it was repainted in its original Indian Red livery and equipped with vigilance control, ICE train radio, and buffers for mainline service.
7350: Owned by Transport Heritage NSW, currently semi-operational at the NSW Rail Museum.

Sold

Several units were sold for commercial use, with some adapted to :

7304, 7306, 7308 & 7341: Stored at the former North Eton Mill shed, owned by Mackay Sugar Limited
7305, 7328, 7330 & 7331: Rebuilt and operational at Farleigh Mill
7309, 7336 & 7347: Stored at Kalamia Mill, Ayr
7310, 7318, 7325, 7346 & 7348: Rebuilt and operational at Invicta Mill
7313: Rebuilt and operational at Pleystowe Mill
7314 & 7339: Rebuilt and operational at Proserpine Mill
7315: Restored and functional at Shoalhaven Starches before partial dismantling; later stored derelict in Bomaderry until removal in 2022; presently kept on private property in Goulburn; formerly owned by Manildra Group after acquisition from Canberra Railway Museum
7317: Rebuilt and operational at Plane Creek Mill
7327 & 7332: Stored in derelict condition at Mackay Sugar Co-op
7337 & 7343: Rebuilt and operational at Marian Mill
7340: Restored and working at Narranderra Mill, under Manildra Group ownership
7349: Retained in original condition at Pioneer Mill, Brandon
7322 & 7333: Owned by Manildra Group and stored; ex-CRT Group units
7319, 7322 & 7333: Acquired by a local Goulburn company; stored at Goulburn Locomotive Depot with unit 7333 undergoing restoration to operational status
7334: Placed on sale list in 2018; presumed sold thereafter

Additional resources