BOOMING demand for iron ore from the hot economies of Asia has added urgency to a programme to raise capacity on the 861 km Sishen - Saldanha line in South Africa.
Built in the 1970s to carry 17·5 million tonnes a year of ore for export, the line was later modernised and upgraded in stages. This included a R542m scheme carried out earlier this decade to raise capacity from 22 million to 29 million tonnes a year. Further enhancement programmes then followed, and last March another upgrade was announced. The current target is to lift capacity to 47 million tonnes a year by 2009.
It was not always so. When demand for iron and steel slumped in the mid-1980s, the line was even considered for closure, although Spoornet management opted for a policy of deferred maintenance. This led to serious problems, and when demand resumed, heavy expenditure was needed to restore the infrastructure back to the high standards required for handling long trains with 26 tonne axleloads, subsequently upgraded to 30 tonnes. Happily, that is now all history, and the line is running near to capacity.
Known as Orex, the line was built by Iscor, the South African Iron & Steel Industrial Corp, and ownership was transferred to Spoornet on April 1 1977. In 2001 Iscor became Kumba Resources Ltd, an independent company listed on the Johannesburg Securities Exchange. The company is now part of Mittal Steel.
The 1 067 mm gauge Orex line runs through virtually uninhabited areas of semi-desert, descending to the coast from a height of 1 295 m above sea level at the Sishen mines. Climate conditions vary substantially, with humidity up to 95% and temperatures ranging from -8ºC to +45ºC.
From Sishen the route rises slightly for 42 km, then descends until it crosses the Orange River at an altitude of 853 m, nearly 700 km from Saldanha. The line rises and falls over the next 300 km, then after the passing loop at Sous drops steadily to the Atlantic coast which is reached about 160 km north of Saldanha. Loaded trains face adverse gradients averaging 0·37% for stretches up to 48 km. Line capacity is restricted due to the unloading facilities at Saldanha being located on a straight spur line on the quay wall projecting into the harbour, rather than on a conventional loop.
A connection with the rest of the network is provided near Vredenburg, close to Saldanha. In the early 1990s another junction was established at Knersvlak, 184 km from the port. Here, since 1994, trains carrying ilmenite, zircon and rutile from a mineral separation plant at Koekenaap have accessed the ore line. The ilmenite is processed at a smelter in Saldanha into high-grade titanium dioxide for pigment manufacture and as pig iron for foundries. Rutile is a raw material used in the manufacture of pigments and as a flux coating on welding electrodes zircon is used in ceramics.
Other traffic originates at Halfweg, 446 km from Saldanha. This consists of lead, copper and zinc concentrates mined at Aggeneys which are transported 178 km by road to Halfweg from where they are railed in both directions.
50 kV electrification
Traffic was first handled by a fleet of 39 General Electric U26C diesel locomotives of 2 750 hp, but in 1977 a decision was taken to electrify the line. The isolated nature of the route meant that 50 kV 50 Hz was the ideal traction voltage, requiring the construction of just six substations compared with as many as 24 had 25 kV been chosen. One issue facing the design engineers was the existence of salt beds near the northern end of the route and the long section following the coastline at the southern end. This meant that the overhead line equipment was exposed to the corrosive effects of wind-blown salt and sand as well as salt-water spray.
Electric motive power took the form of 25 Class 9E locomotives assembled by Union Carriage & Wagon, and electric haulage began in 1978. A further six Class 9E locomotives were supplied in 1982-83.
The 9E traction package including thyristor control was supplied by GEC Traction from Britain. A continuous UIC rating of 3 780 kW at 34·5 km/h made the Class 9E the most powerful 1 067 mm gauge electric locomotive in the world when it entered service. With a starting tractive effort of 554 kN, three locomotives in multiple were able to start the heaviest train on a 0·4% grade.
The Class 9E fleet is now being upgraded under a R180m contract awarded to Alstom in 2000. By the end of 2006, 19 upgraded locos were back in service, and completion of all 31 is scheduled for mid-2007.
The equipment designed and supplied by Alstom is being installed by Transwerk, Transnet's rolling stock maintenance subsidiary, which is responsible for overhauling other equipment on each locomotive.
The main thrust of the upgrade has been to replace analogue controls with Alstom's Agate digital technology. Modern braking resistors, new gear cases and the facility for multiple operation with diesel locomotives are other important improvements.
The overhaul of traction motors, the 50 kV main transformers and the specially-designed four-bottle series vacuum circuit-breakers have been spread among Alstom's different divisions in South Africa. Driver comfort has been improved thanks to a cab redesign following the latest ergonomic principles.
Better technical stability, more units in service and higher monthly distances are reflected in improved reliability. Once the upgrade programme is complete, the reliability target will be 40 000 km between failures.
The electrified line was originally worked by trains of 20 200 gross tonnes hauled by three locos in multiple. In 1980 a test train ran successfully with a load of 22 626 tonnes, following which regular loadings were increased to 21 840 tonnes and later to 22 880 tonnes in 216-wagon trains, each 2·2 km long.
Line capacity has since increased significantly but although plans were made to acquire additional locomotives, no new order was placed until 2006. In the meantime Spoornet drafted in Class 34 diesel-electric locomotives to augment the Class 9E fleet.
Wagons are semi-permanently coupled in pairs with rotary couplers at the outer end of each pair for unloading in a tandem tippler at Saldanha. Type CR5 wagons with a capacity of 33·3 m3 were placed in service in 1978 and these were followed in 1994 by Type CR12 wagons converted from earlier types CR9 and CR10. In a R220m project begun in 1999, 166 new CR13 wagons were manufactured by Transwerk. Nearly 1 000 CR5 units were uprated to 100-tonne capacity to match the CR13s at a cost of R170m, and redesignated CR14.
To meet future demand, Spoornet needs to increase train lengths from 216 to 342 wagons. One limitation is the coupler force, which cannot exceed 1 600 kN. The margin on a 216-wagon train is small, as the coupler force required is 1 300 kN. Longer trains will require locos to be inserted mid-train, with control by radio from the lead loco.
A 3·9 km test train with a payload of 34 300 tonnes was run in August 2004 using voice radio to communicate with drivers on mid-train locos. The trial was successful enough for modifications to be incorporated into the loco upgrading programme, and some of the modified locos have been used in service trials of distributed power. The aim is to assemble trains formed by three consists, each with 114 wagons and a loco on each end.
Concession plan thrown out
In 2000 the UK-based Rothschild merchant bank recommended that Orex be let to a concessionaire, but this policy met strong opposition from trade unions, leading to several years of indecision. For instance, plans to purchase new locomotives were authorised but never carried through.
Inaction soon led to protests from customers who claimed that their requirements were not being met. In 2004, Kumba Resources calculated that it was losing US$500m a year in export potential due to shortcomings in rail service, frustrating its ability to meet ever-growing demand in the Far East. The company was prepared to purchase two complete trains itself, but Transnet CEO Maria Ramos declined the offer, saying 'it does not necessarily make business sense'. Finally, agreement was reached that the ore line would not be privatised, and long-overdue development went ahead.
Progress was initially hampered by the contract with Kumba, because it was dollar-based. Spoornet was obliged to treat the agreement as an embedded derivative, calculating its all-in liability at about US$1·5bn, of which almost half was booked in the company's poor 2004 results. Early in March 2005, Kumba signed a new 23-year agreement with Transnet. Calculated in Rand, it is reviewed every five years. Transnet then undertook to increase Kumba's ore loading through Saldanha from 23·5 million tonnes a year to 35 million by 2009. The mining company immediately initiated long-planned expansion at Sishen worth US$500m.
Just 18 months later, in a long-awaited announcement, Spoornet CEO Siyabonga Gama disclosed that 32 Class 15E locomotives were being ordered for the ore line under a R1·12bn contract. A second phase order is expected to bring the total to 42 locos.
This was the second major investment deal to be announced in 2006 following an earlier order for 110 dual-voltage locos for Spoornet's heavy haul coal line serving Richards Bay. Both orders were part of a R31·5bn five-year capital investment programme.
Work on the new 50 kV locomotives has already begun, with delivery to be completed by 2009. Design, manufacture and supply is in the hands of the Union Carriage & Wagon Partnership in conjunction with Mars & Venus Railway Solutions, a special-purpose vehicle between Mitsui & Co Ltd, Sibambene Trade & Services Holdings (Pty) Ltd and African Sky Innovative Solutions (Pty) Ltd. Mitsui has a 55% share in the company and the BEE partners (in conformity with South African Black Economic Empowerment requirements) own the remaining 45%. The main subcontractors are UCWP and Toshiba. Around 43 companies are involved, with a BEE component ranging from 5% to 100%.
The Class 15E will be the most powerful in the Spoornet fleet with a continuous tractive effort of 480 kN compared with 383 kN attained by the Class 9E. The 15Es will be maintained at Salkor Yard near Saldanha, where work on a dedicated maintenance facility is already in progress. Once the 15Es are in service, the diesels used to supplement the Class 9E fleet will be withdrawn from the ore line.
The 15E will offer several important technical innovations including GPRS from Toshiba, touch-screen cab displays and the monitoring of all trip and technical data for automatic downloading via wayside readers. According to UCWP Managing Director Palello Lebaka, the locomotives are being designed and constructed in modules that are huck-bolted rather than welded using traditional methods - the first time that huck bolting has been applied to locomotive construction in South Africa. Significant time savings accrue because several assembly functions are performed in parallel.
Since the start of operations all movements have been controlled from Saldanha by CTC in conjunction with microwave and VHF radio. The line was built with 10 passing loops at intervals of 80 to 90 km, but these have since been augmented by another 10. Turnouts at each loop, controlled from Saldanha, are protected by three-aspect colourlight signals. Absolute block working is applied in all block sections between loops, using last vehicle detection equipment.
Resignalling is now in progress, and Siemens Transportation Systems was awarded a R90m contract which should see the work finished in March 2008. The company is supplying 20 SIMIS S electronic interlockings and 60 axle-counter installations.
Track wear addressed
The 25 m long, 60 kg/m chrome-manganese rails were flashbutt welded into 300 m lengths at Saldanha and then transported to site for aluminothermic welding into CWR. The rails performed satisfactorily, although some problems did arise. These were found to be related to tight gauge and to hunting of the electric locomotives this was addressed by fitting inter-bogie control systems and by moving the wheels closer together on the axle.
The appearance of head checks on the high rail in curves and in areas of sinusoidal side wear was tackled by reprofiling and consistent wheel profile maintenance. Local dipping of flash-butt welds proved a more serious problem, and a method of improving the hardness profile over welds by means of induction heating was developed.
During the 1990s, cracking running parallel with the pre-stressing wires occurred in the concrete sleepers. This was attributed to alkaline aggregate reaction (RG 6.97 p361). Where only slight cracking was evident, sleepers were treated with a hydrophobic solution, but elsewhere replacement was necessary.
The original 1:12 and 1:9 sets of points, including timbers, were imported from Klockner in Germany. These are being replaced on the main line with 1:20 turnouts, and 20 have been installed so far. Alstom Railway Signalling has supplied its C1H point machines, with 110 V DC equipment controlled by a two-wire system instead of the more conventional three-wire arrangement. In a subsequent contract, 41 C1H hydraulic machines were supplied for the 1:12 turnouts.
The line has 82 bridges, the longest of which crosses the Olifants River. At 1 035 m, it consists of two sets of 11 x 45 m continuous spans fixed at the abutments, plus a 45 m span supported in the centre. After a costly derailment in 1982, attributed to a track kick-out caused by excessive compressive forces in the CWR, the sleepers on the bridge were replaced with specially designed winged-type bearers. Stresses are now monitored continuously, with a warning sent to the CTC operator if any irregularity occurs.
Halfweg is the only station on the entire route. Crews are changed here, but studies are underway into different crewing arrangements to suit new working time regulations.
By 2005 the line was operating at near-capacity. Several different types of work needed to be carried out before any further capacity could be squeezed out of the line, and Spoornet decided to implement a 10-day blockade last August to carry out as much work as possible in the shortest time.
During the R76m programme, maintenance and enhancements were carried out simultaneously along much of the route. Work included installation of 20 turnouts, relaying 40 000 sleepers, grinding 500 km of rail, screening ballast over 79 km, and replacement of two culverts.
Spoornet has also decided to improve the power supply by installing additional substations. This will allow trains to operate with five or possibly six locomotives. Detailed design for upgrading both the Eskom and Spoornet power networks is in progress. In the near future, train turnround times will be shortened by raising the loading speed at the mines to 5 400 tonnes per hour.
Work was due to start in May on lengthening the passing loops from about 3·6 km to 4·4 km. Three separate contracts cover loops 2 to 8 and a new Loop 7A, loops 9 and 11, and loops 12 to 19. Due for completion by July 2008, this will allow the introduction of regular trains of 342 wagons.
By the end of this year, Kumba's ore output at Sishen will have reached 44 million tonnes a year. A further six million tonnes come from the second producer, Assmang, which is aiming for 10 million tonnes a year by 2010.
A new 30 km direct line, electrified at 50 kV AC, is proposed south of Sishen which will serve Beeshoek iron ore mine and subsequently a 15 km extension to a new mine at Sishen South. At present, traffic from Beeshoek is hauled by 3 kV DC electric locomotives using the freight Postmasburg - Hotazel line. Trains access Sishen Yard by means of a connection to Orex. However, the Hotazel line is running at capacity and cannot cope with the proposed increase in production at Beeshoek, even before Sishen South comes on stream. The new line will connect into Orex at an enlarged siding facility at Loop 19 by 2010.
Matching improvements are taking place in Saldanha. Following recent environmental approval, capacity of the ore terminal is being raised from 38 million to 45 million tonnes a year.
This dovetails with Transnet's latest capital expenditure programme authorised in September 2006 to increase capacity on the line beyond the previous target of 41 million tonnes annually to 47 million, which is to be reached in 2009. In the meantime feasibility studies have been put in hand for further expansion to 67 million tonnes a year, the ultimate long-term aim being to reach 93 million.
- CAPTIONS: Spoornet is using Class 34 diesels to augment the Class 9Es on heavier iron-ore trains, but delivery of the Class 15E locos and upgrading of the power supply will permit all-electric operation in the future
- Spoornet's Orex line carries iron ore from Sishen and other minerals that are trucked from Aggeneys to Halfweg for onward shipment by rail
- Upgrading work included the installation of new 1:20 turnouts during a 10-day blockade in August 2006
- Alstom is working with Union Carriage & Wagon Partnership to upgrade the fleet of 31 Class 9E locomotives with microprocessor controls the work includes a revised driver's console
- The 1 067 mm gauge Orex track is designed for 30 tonne axleloads
- An RM200 ballast cleaner progresses through a loop while the line was closed during a 10-day blockade last August
- A ballast cleaner with spoil wagons works across the Orange River bridge during the August blockade last year
- Type CR13 ore wagons are designed to carry 100 tonnes of ore
L'amélioration de la ligne Orex vise une capacité accrue
Des trains plus longs utilisant une motorisation répartie et un parc de nouvelles et puissantes locomotives 15E sont les éléments clés d'un nouveau programme destiné à augmenter la capacité de la ligne Orex, la ligne à trafic lourd de Spoornet, longue de 861 km. Construite dans les années 70 pour transporter 17·5 millions de tonnes de minerai de fer par an venant des mines de Sishen jusqu'au port en eau profonde de Saldanha, la ligne est électrifiée en 50 kV 50 Hz. Les plus récents programmes de modernisation ont porté la capacité à 29 millions de tonnes par an et le but du moment est d'atteindre 47 millions de tonnes par an d'ici à 2009. A plus long terme, l'opérateur national d'Afrique du Sud envisage d'autres expansion de telle sorte que la ligne Orex puisse acheminer 67 millions de tonnes et finalement 93 million de tonnes par an
Orex-Ausbauten ermöglichen höhere Kapazität
Längere Züge mit verteilten Triebfahrzeugen und eine Flotte von leistungsfähigen Lokomotiven der Baureihe 15E sind Schlüsselelemente in einem neuen Programm zur Steigerung der Kapazität der 861 km langen Orex Schwerlaststrecke von Spoornet. Die in den 70er-Jahren des letzten Jahrhunderts gebaute Strecke für den Transport von 17·5 Millionen Tonnen Eisenerz von den Minen in Sishen zum Hafen von Saldanha ist mit 50 kV 50 Hz elektrifiziert. Das letzte Ausbauprogramm brachte eine Kapazitätssteigerung auf 29 Millionen Tonnen, und das Ziel des aktuellen Programms ist 47 Millionen Tonnen pro Jahr in 2009. Langfristig plant der südafrikanische Betreiber weitere Ausbauten, so dass Orex 67 Millionen Tonnen und schliesslich bis zu 93 Millionen Tonnen pro Jahr transportieren kann
Orex se actualiza para lograr una mayor capacida
Trenes de mayor longitud con tracción distribuida y un parque de potentes nuevas locomotoras del serie 15E son elementos clave en un innovador programa para aumentar la capacidad de la línea Orex de mercancías pesadas de Spoornet que cubre 861 km. La línea se construyó en los años setenta para transportar 17·5 millones de toneladas de mineral de hierro al año desde las minas de Sishen hasta el puerto de aguas profundas de Saldanha y se electrificó a 50 kV 50 Hz. Los programas de actualización más recientes aumentaron la capacidad a 29 millones de toneladas al año y el objetivo actual es lograr 47 millones de toneladas al año para 2009. A largo plazo, el operador nacional de Sudáfrica prevé una futura expansión, gracias a la cual Orex podrá transportar 67 millones de toneladas y, en última instancia, 93 millones de toneladas al año