THESE are difficult times for the iron-ore miners of the Pilbara region of Western Australia. From a peak of $US 187.18 per dry tonne in February 2011, global iron-ore prices plunged to $US 51.50 per dry tonne in July, their lowest level since the end of 2007 and with a glut in supply, analysts predict prices could dip to $US 40 by the end of the year.
Against this backdrop, the efficiency of the supply chain plays an even more valuable role in ensuring the region's mines remain competitive - and therefore viable - operations. Rail is the primary link to port for most of the large mines in the Pilbara and the mining companies, which own the infrastructure, are continually seeking new ways to enhance the performance of their railway operations.
This culture of constant improvement is clear to see on the Fortescue Railway, which is owned and operated by Fortescue Metals Group (FMG). Construction of the 288km line from Herb Elliott Port at Point Anderson near Port Hedland to Cloudbreak in the Chichester Ranges began 10 years ago this month and despite damage from a cyclone, which killed two construction workers, the line opened in April 2008.
Expansion of the railway was rapid as FMG worked towards its target of increasing the output of its Pilbara mines to 155 million tonnes per annum (mtpa). A 40km extension from Cloudbreak to Christmas Creek mine was commissioned in 2010 and in December 2012 FMG's opened a branch to its Solomon Hub in the Hammersley Ranges, which serves the Firetail and Kings mines.
In an environment where temperatures can range from below freezing to more than 40oC, the Fortescue Railway is built to cope with extremes. Structures and earthworks are designed to withstand 1-in-100 year weather events - when the rains come to this arid region, dry river beds quickly become raging torrents which in some cases can be several kilometres wide. Following storms, inspections are carried out using helicopters and road-rail vehicles in order to quickly restore operations.
Fortescue claims to operate the longest and heaviest trains in the world using only head-end power. Two or three locomotives provide traction for each loaded 250-wagon train, which is 2.7km long and weighs around 40,000 tonnes, with a payload of 35,000 tonnes. When the line opened the maximum axleload was 40 tonnes, increasing to 42 tonnes in November 2014 and FMG says it can now operate up to 43.5 tonne axleloads. FMG has been working in partnership with SKF to develop a 45-tonne axleload bearing, which is now fitted to 140 of its ore wagons.
The railway typically operates 14 or 15 trains per day with single-man crews from the mines to Port Hedland with an average cycle time of between 19 and 21 hours. Loading takes around 2.5 hours, while unloading at Port Hedland takes around three hours for a complete train, with a rotary dumper tipping pairs of wagons which remain coupled to the train during unloading. A banking locomotive provides assistance on the first section of the journey to the coast and automatically decouples while the train is in motion.
Utilisation of the fleet of six-axle GE and EMD locomotive is high, with each unit averaging 530MWh per month. The fleet comprises a mixture of 3.28MW-output dc traction GE Dash 9-4400CWs and 3.4MW EMD SD70ACes, which are equipped with ac traction motors.
FMG operates 19 rakes of wagons supplied by CSR Zhuzhou, China, which are equipped with electronically-controlled pneumatic brakes (ECP) supplied by New York Air Brake, enabling a full-length loaded train to come to a stand within 800m on level track. Each wagon has a tare weight of 23 tonnes and 69m3 internal cubic capacity.
Operation
In December 2013 FMG completed the migration of its signalling from a train order system to a communications-based Integrated Train Control System (ITCS), which is described as the first deployment of its kind in Australia.
ITCS utilises GE's Positive Train Control (PTC) technology to control the movement of all trains, track maintenance vehicles, and road-rail vehicles on the railway. An onboard unit communicates with the trackside ITCS server to determine the position of switches, temporary speed restrictions, and the location of other trains. The onboard computer feeds data on infrastructure parameters such as gradients, curvature, line speed, and braking distances to the driver via an MMI in the locomotive cab, which also displays a "virtual signal" indicating the signal status and the limit of the movement authority for the train. If the driver fails to slow the train within the calculated braking curve, an automatic brake application will occur to prevent the train exceeding its movement authority.
The average length of track circuits on the Fortescue Railway is around 8km, but the introduction of ITCS has enabled operation with 4km virtual blocks, reducing headways - a particular advantage on the approach to the port. The system has also reduced the need for trackside signals and transponders, minimising maintenance costs.
Most of the 150 signalling units are solar-powered, reducing the need for cabling and power supplies, a particular advantage in remote territory. FMG says its batteries have enough capacity to continue functioning normally through five days of continuous cloud cover, an unlikely scenario in this arid desert region.
Operations are supervised by a dedicated traffic control centre located 1300km away in Perth, which also remotely controls unloading at Port Hedland. The whole railway is covered by just three controllers - one for the unloading facility and balloon loop at Port Hedland, one for the mine, and one for the line itself.
The entire railway is covered by a Tetra radio network, providing voice-only data transmission to around 800 terminals via a network of 24 radio base stations.
In order to optimise operations and reduce the risk of disruptions FMG relies on a suite of remote monitoring technologies including bearing acoustic monitoring, wheel impact load detectors, and hot bearing detectors, which are positioned at 50km intervals along the route. Instrumented locomotives and wagons constantly gather data on the condition of the infrastructure.
Grinding is key to maintaining high-quality heavy-haul infrastructure and the railway operates a Loram 4000 Series 60-stone grinding machine, which achieves average speeds of 18km/h for single-pass grinding and can cover more than 80km a day. While the grinder can automatically check for railhead defects, FMG has adopted a preventative approach to rail grinding to minimise the risk of disruptive incidents.
Automated maintenance
Initially the railway had capacity to maintain four rakes of ore wagons (986 vehicles) and 15 locomotives, but with the 155mpta expansion, maintenance facilities and methodologies needed to evolve to accommodate a larger fleet and more demanding operating requirements. Maintenance of the fleet is based on a combination of predictive and preventative schedules, which are continually being refined to minimise downtime.
Automation of the ore car workshop (OCW) at Thomas Yard in South Hedland has reduced manual handling and transformed rolling stock maintenance into a production line process capable of servicing up to 5500 vehicles per year. The workshop was completed in July 2013 and officially opened in October 2013.
Achieving a return on the investment and a safer working environment were identified as the primary aims of the OCW project at the development stage. Existing maintenance processes were reviewed and feasibility studies, risk assessments and design reviews were carried out to identify which automation options would meet FMG's requirements.
Five production lines at the OCW employ a safety-cell methodology, where the lines are enclosed by a mesh fence with access doors which are interlocked with the automated control system, preventing entry when machines are operating automatically. If access is required, the maintainer presses an entry button, returning the machine to its home position. Safety cell processes include wheel profiling, wheel boring, axle requalification, wheel demounting, and magnetic particle inspection. The status of all machines can be monitored from outside the safety cell.
The OCW has two through maintenance roads, which enable 12 wagons to be shunted onto the entry apron. The aprons are protected by buffer stops which prevent any uncontrolled rail movements inside the depot building. The buffer stops are controlled by a "Cub", which automatically propels the wagons into the workshop when safety permission has been granted. The Cub can then shunt two pairs of wagons into position in each of the two lifting bays, which are equipped with Eurogamma jacks. The jacks operate simultaneously, enabling removal of the wheelsets, which are moved in pairs by a remote control tug via a series of turntables to the reprofiling line. The use of the tug reduces the requirement for forklifts and crane movements.
Following end cap removal and visual inspection, the wheelset data is entered into the automatic control console and sent to the Production Control System (PCS) which manages the wheel profiling line. A metrology station automatically measures parameters including wheel profile, back-to-back, rim thickness, wheel diameter and wheel width, before the wheelset passes through the bearing demount station.
After a wire brush station automatically cleans the bearing journal to remove any scaling or contaminants the wheelset proceeds to the bearing journal measuring station. If the wheelset fails at this stage it is transferred to a bypass line for re-evaluation. The next stage is reprofiling on the Hegenscheidt portal lathe, which automatically machines the wheelset and carries out measurements, which are captured by the PCS, before the wheelset continues to the ultrasonic inspection station and bearing journal lubrication station. Bearing mounts are then automatically refitted before a maintainer carries out a final check of the wheelset and installs the end caps.
FMG says the automation of the OCW has been a hugely successful project, significantly reducing manual handling and minimising cycle time while dramatically increasing maintenance capacity. The PCS has transformed the tracking of components on the car fleet and provides a valuable extra tool for engineering analysis, with all data from the automated processes stored for future use.
Amsted Rail prepares for higher axleloads
AMSTED Rail is developing new designs of components to produce a bogie to meet the demand from Australian heavy-haul freight railways for 45-tonne axleload freight wagons, or even 50-tonne axleloads in the future.
Prototypes of a new bearing called the Mega-tonne, which is designed for 45-tonne axleloads, have been completed and will soon start trials with operators in Australia.
"Customers also want more reliable bearings," Mr Jay Monaco, vice-president of global engineering with Amsted Rail, told IRJ at Railway Interchange. "The Mega-tonne can work with an AAR Class G axle, and with minor modifications to the sideframe pedestal, we can accommodate this larger bearing."
The next phase to move from 40 to 45-tonne axleloads involves developing an appropriate bogie. "It is quite a challenge to produce a 45-tonne axleload bogie because all the equipment is larger and needs more space," says Monaco. "Wagons are also becoming lighter but the loads are getting heavier which affects dynamic performance, and we also need good curving performance.
"Our Super Service Ride Master bogie will act as the platform for the new 45-tonne bogie," says Monaco. "We have produced special suspension springs for it and made new castings. These are now going through structural and dynamic tests to AAR standards to validate the design and we should be ready to start field trials by the end of the year."
Roy Hill Railway ready for launch
NOT FAR from FMG's Port Hedland terminal, another new heavy-haul line is due to begin operating within the next few months. The Roy Hill Railway an independently-owned and operated line linking the new Roy Hill Mine with a dedicated unloading facility at Boodarie Industrial Estate south of Port Hedland.
The 344km line is designed to carry up to 55 million tonnes of hematite ore per year and Roy Hill will operate five trains per day, each formed of two locomotives and 232 wagons with a total payload of 31,132 tonnes. With a ruling gradient of 0.6% on the climb out of the mine, a manned banker locomotive assists the train on the first 30km of its journey to the port. All 21 GE Evolution Series locomotives in the Roy Hill fleet are equipped with GE's Locotrol distributed traction system.
CSR has supplied a fleet of 1196 ore wagons, which are the first in the Pilbara to be fitted with stand-alone ECP brakes supplied by New York Air Brake. Each 40-tonne axleload wagon has an internal capacity of 70m3 and runs on variable damped bogies with ECP brakes in a two-car control/slave configuration.
The line is single track with four 3.2km passing loops, which are positioned to optimize the cycle times of trains.
Trains are loaded at the mine using an overhead loader controlled from the Remote Operations Centre in Perth. Loading takes around 2h 40min and the loaded train then travels non-stop to Port Hedland, where it is unloaded using a rotary dumper, which tips
two wagons at a time in an 88-second cycle.
The line is equipped with moving block signalling, with automated route setting and train control managed from a remote operations centre in Perth.
