Commonwealth Engineering

Commonwealth Engineering

Commonwealth Engineering (Com-Eng) was a major Australian engineering firm that designed and built railway rolling stock. While best known for their work on standard and broad gauge passenger stock for state railways, they produced a significant number of diesel locomotives for the Queensland sugar industry during the transition from steam to internal combustion power in the 1950s and 1960s.

History

Com-Eng entered the sugar cane locomotive market in the mid-1950s. Their locomotives were manufactured at their Rocklea works in Brisbane, Queensland. The company established a classification system to denote the various models they produced, initially using a single letter code, and later a two-letter code where the first letter indicated the general type and the second indicated engine or transmission variations.

The company ceased production of cane locomotives as the market saturated and other builders like E.M. Baldwin and Clyde Engineering became dominant in the heavier horsepower categories.

Models and Classification

The Com-Eng classification system for sugar industry locomotives is as follows:

• Type A: 0-6-0 Diesel Mechanical or Diesel Hydraulic. These were typically 14 to 18 tonnes with power output ranging from 150 to 205 hp.
• Type C: 0-4-0 Diesel Hydraulic. A lighter shunting unit weighing 9 to 12 tonnes with approximately 112 hp.
• Type F: 0-6-0 Diesel Hydraulic. A heavier unit for the time, weighing 19 to 25 tonnes with 250 to 277 hp.
• Type G: 4-wheel Diesel Mechanical. Very small units weighing 4 to 8 tonnes with 76 hp.
• Type N: B-B Diesel Hydraulic.

Production Notes

Until 1959 (up to serial number 35), classification was by the initial letter only. Later, a more complex scheme was introduced, and these codes were often applied retrospectively. The numbering system typically used the first two digits to denote the variant code (starting from 10) and the final digits as the serial number.

Significant Allocations

Com-Eng locomotives were found at mills right across the state, from the Southern districts to the Far North. Notable examples include the fleets at South Johnstone Mill and Mulgrave Mill, where they served as the backbone of the diesel fleet before the introduction of larger bogie locomotives.

Sources

• Light Railway Research Society of Australia (LRRSA).
• Notes on Locomotive Classification and Numbering (Historical Document).
• Zelmer, L. (2004). Australian Canefield Locomotives.