SINGLE COMMODITY railways have several advantages over mixed traffic railways when it comes to productivity comparisons. All trains, for example, may be of the same formation and same weight, allowing the best use of line capacity. Nonetheless, it is instructive to see just what is being achieved by the iron ore railways operating in the Pilbara in northwestern Australia.

The accompanying graphs, prepared for a recent BAH-Indec report, were presented to delegates on the IHHA’s Pilbara railways study tour in June by BHP Iron Ore, which has been at the forefront of research into heavy haul operations in recent years. Much of the research has been carried out with Monash University, which in January 2000 took over BHP’s internal research facilities. BHPIO’s achievements are in the top of the range, but note too the locomotive performance attained by Hamersley Iron (652·8 million tonne-km/loco per year), and the tonne-km per employee reached by all three Pilbara railways (Fig 3).

It is worth noting that BHPIO’s research programme has been continuous for nearly 30 years, a prime objective having been to minimise operating and capital costs. Much of the work has centred on the wheel-rail interface, but the programme has spawned changes in equipment, materials and specifications.

During the 1990s operating costs per tonne-km were halved, due in no small measure to systematic application of improvements. Since 1970 wagon payloads, measured in wet tonnes per wagon, have risen from 89 to 126, with axleloads increasing from 28·5 to 37·5 tonnes. Rail life has been increased and track lubrication has been discarded thanks to an effective programme of grinding and rail husbandry. Hunting has been virtually eliminated, and wheel life extended from 340000 km to around 2 million km. Bridges have been rerated to accept 40 tonne axleloads from an initial design level of 32 tonnes.

Achieving these results has not always been without problems, and many lessons have been learnt. At the moment, for example, BHPIO is working with GE Transportation Systems to improve its fleet of eight AC6000CW locomotives, which generate a remarkable starting tractive effort of 890 kN. Their three-axle steerable bogies have given rise to problems that included asymmetric wheel wear and vibrations, requiring replacement of some components. The cab air-conditioning has also come in for criticism, and BHPIO says it did not really meet the specification for operation in temperatures of up to 60°C.

Other recent problems have included a spate of rail breaks, mainly at weld points, which was exacerbated by colder than expected weather.

BHPIO continues to work with Monash, and more improvements are in the pipeline. These could include an increase in speed on downhill sections above the present 75 km/h limit to reduce trip times and cut fuel costs, possibly saving up to A$1m a year.

BHPIO meanwhile expects to close the mine at Yarrie in around four years, but by that time it could be hauling ore from the Hancock deposits at Hope Downs, to be reached by an extension of the Yandi branch. Bodies for the necessary ore cars are currently in store, and could be quickly restored to use if the project goes ahead.

CAPTION: Fig 1. Annual rolling stock productivity as determined in BHP’s benchmarking study

CAPTION: Tony Godber, Superintendent, Rail Operations, at Hamersley Iron, oversees the world’s most productive locomotive fleet

CAPTION: Top: Fig 2. Annual traffic density in net tonne-km per route-kmAbove: Fig 3. Annual productivity by member of staff employed