Starved of investment in recent years, the nation’s rail infrastructure renewal is back on track thanks to a significant financial shot-in-the-arm for KiwiRail in May’s budget. CHRIS WEBB reports.
CONSCIOUS, PERHAPS, OF the fact that ‘Project Ongaruhe Optimised Seven – North Island Main Trunkline Rail Bridge replacement’ doesn’t exactly excite in the same way as a new James Bond movie, KiwiRail has instead dubbed it with the shorthand ‘OO7’.
The work involves upgrading seven wooden railway bridges on the North Island Main Trunkline (NIMT) in the Taumarunui area and a further one in Taupiri. Begun in February, the project is being undertaken by KiwiRail’s contractor, Downer New Zealand. It will help improve the network and allow more freight to be carried on the tracks in future.
In May, KiwiRail welcomed the funding package included in the government’s Budget announcements in which it will receive $210 million in 2015/16 and a further $190 million as a pre-commitment against Budget 2016.
“The package recognises the vital role that KiwiRail plays in New Zealand’s transport networks and the significant economic, social and environmental benefits it contributes to New Zealand,” says KiwiRail chief executive Peter Reidy.
Transport Minister Simon Bridges said the investment was necessary to develop the system with a view to “making the freight business a viable concern”.
Reidy continues: “Government investment in our business over recent years has enabled us to make significant improvements in the quality of our service offering, meaning we’ve become a more efficient and reliable supply chain partner.
“This has been reflected in the significant growth in freight volumes carried over that period, supporting the government’s ‘Business Growth Agenda’. We’ve also seen increased patronage on our passenger rail and Interislander ferry businesses during that time.”
The work includes replacing a total of eight weathering steel bridge superstructures. Downer New Zealand CEO Cos Bruyn says the design and construction contract is valued at $24.3 million.
“This is familiar territory for Downer, we are utilising all our experience and knowledge, and the project has been carefully planned months in advance in order to ensure minimum disruption.
“We will be working carefully around the existing fragile structures, as well as overcoming the challenges of working with live rail lines and overhead power lines, and dealing with liquefiable and soft soils,” he told Contractor.
“Downer has a strong relationship with KiwiRail having worked previously on the EMU Depot in Wiri, Bridge 28 Replacement, Palmerston North Yard upgrade plus a range of previous civil and maintenance contracts.”
Bruyn says the contract involves some significant technical challenges.
“The OO7 project is a design and construct contract. Safety is always our highest priority, and this project is no different, particularly when working around live rail lines with traction and live overhead power lines. Some of the key technical challenges are similar to other design and construct projects, where strong temporary works or tight schedules are a must.
“We’ve had to consider economical designs to deal with liquefiable and soft soils, and strong temporary works design to ensure the bridges remain online and safe when working with the existing fragile structures. This requires thorough planning and exceptional temporary work design.
“We continue to work towards fixed block-of-lines to complete the changeovers – all of which are locked-in months in advance. Programme targets must be met and most block-of-lines are scheduled over public holidays so resources need to be locked in well in advance.”
Work is well advanced on two of the bridges – Uepango Bridge (206), and Taringamotu Bridge (203). A new culvert is being built in the Uepango Stream, requiring temporary diversion of the existing stream to maintain water flow during construction. To stabilise and strengthen the surrounding ground sheet piles and a concrete capping beam have been installed as foundations for both the culvert and new retaining wall on the eastern side of the bridge. A similar arrangement is being installed on the bridge’s western side.
Upgrade works at the northern embankment of Taringamotu Bridge include mass stabilisation of the existing embankment and the installation of 50 titan minipiles to stabilise the ground.
KiwiRail construction manager Peter Dautermann says the ensuing benefits of the scheme will include reduced maintenance and rail noise but also a number of economic benefits.
The first milestone at Taringamotu was the completion of two out of five sections of the bridge over Queen’s Birthday weekend. Dautermann says it was a busy 24 hours for the teams, who replaced two spans of the old bridge with an 18-tonne precast concrete deck.
The crew built up the embankment, placed the ballast and relayed the tracks. Heavy machinery was used to complete the works, including a 100-tonne crane, another smaller crane, 360-degree excavators and rollers.
In the South Island, an early January 2015 earthquake of magnitude 5.6 brought New Zealanders a sharp reminder of the devastating events of 2010 and 2011, which flattened much of Christchurch. It also brought much of the rail network to a standstill, temporarily at least, while engineers checked the system’s safety.
KiwiRail was quick to declare the main North Line between Oaro and Christchurch, and the main South Line between Oamaru and the city, along with the Hokitika Line, clear to reopen. No serious issues were reported, Ron Murray, KiwiRail’s spokesman for operations reported at the time. Nevertheless, the largely benign earthquake, some 44 kilometres to the south-southeast of Hokitika, on January 5, 2015 near Arthur’s Pass and Methven, highlighted the importance of recent and extensive reconstruction works to upgrade the network.
“The 2010/11 earthquakes, along with a number of other significant quakes in recent years in the South Island as well as the Wellington region prompted KiwiRail to undertake an assessment of its portfolio of buildings across the country and to strengthen those buildings and other infrastructure as required,” Murray told Contractor.
These works had already seen activity in the North Island include the Wellington Metro Upgrade Project (WMUP) which is, over the next eight years, set to deliver significant improvements to aging overhead traction systems and signalling across the network. The work is in response to many years of under-investment, and is needed to support the Wellington commuter system.
“Under-investment in New Zealand’s rail system is a well-recognised fact and since 2004 KiwiRail has been increasing the investment in the upgrade of its infrastructure,” explains Murray. For bridges, the annual budget has increased from some $10 million a year in 2004 to $40 million in 2010 and has remained at around the $30-$40 million level over the past five years. Currently, KiwiRail has a network of around 3940 kilometres of track, and is currently operating on 3460 kilometres of it. Infrastructure includes a total of 1489 bridges, serving 189 mainline locomotives and around 4740 freight wagons.
Recently completed, the Wellington Region Rail Programme (WRRP) prepares lines for the introduction of the new Matangi trains. The work included double tracking to Waikanae, constructing a third track into Wellington Station and improving the traction overhead to carry more power. Benefits include increased train speed, improved timekeeping for trains, a reduction in the number of random faults and the provision of more train services to cope with growing demand. The WMUP, currently underway, will build on this and result in better network operability.
The capital aside, just as important are the ongoing works in the South Island, which is a major contributor to the country’s tourism and coal-mining industries. Timber-decked bridges, most of them at least 100 years old, are being replaced in a rolling programme. Among them are those between Lyttelton and Christchurch, the first suburban electric train service in the country.
“This timber elimination programme could definitely be described as a ‘rolling programme’,” says Murray, “in the sense that it is ongoing and will continue for another 25 to 30 years. There are some 500 bridges containing timber piers and timber spans, and it will take a long time to replace all of the timber structures.
“The bridges are not being replaced in a sequential fashion [from one bridge to another]; rather, they are being prioritised using a combination of risk assessment taking into consideration their individual condition and strategic importance of the various line segments,” says Murray.
The vast majority of the bridges concerned are replaced ‘in line’, in that they are being replaced in exactly the same location as the existing structure. New piers are built within the ‘live’ corridor around train movements over a few months – depending on the number and depth of the new piers (during a ‘block of line’ or track possession) where there are no train movements at all. This operation is usually undertaken during a 24- to 48-hour operation in which the old bridge is taken out, the new bridge deck is lifted in or assembled and the track re-instated.
Typical of the many bridge replacement projects is that of Bridge 72 on the Midland Line, where last year Smith Crane and Construction (SCC) installed two 14-metre concrete ballast deck spans on new concrete piers and abutments. All of the works prior to the bridge change-over had to be carried out in the live railway corridor in-between trains. The bridge change-over was carried out and completed within a 36 hours possession.
Clive Baddeley, civil engineering manager at SCC, says the project at Camp Creek marked the end of a successful five-month bridge operation in bad weather. The civil works involved the construction of piers and crossbeams to support the new decks.
“Temporary works involved the design and fabrication of a specialised falsework system to support the headstock soffit,” he says.
“After column curing, the headstock soffits were bolted [to] either side of the columns, and propped from below. The handrails were pre-attached to provide a safe platform. A pre-tied cage was then lifted onto the soffit, and steel forms bolted on. After that, the inserts were accurately placed between the bars and their location double checked and made secure.”
Then came the casting of the headstocks themselves.
“The precast deck units were manufactured on site, as we had previously done on bridges 41 and 61 on the Midland Line. A series of concrete pads was cast for the steel deck mould to sit on. After each cast, the unit was lifted and the mould moved to the next cast location; reinforcement, stressing ducts and cast-in items were fixed in the mould.”
The 65MPa concrete was sourced from Allied Concrete in Timaru, pours taking place in the early morning to allow sufficient finishing time.
Once adequately cured, the deck unit was jacked out of the mould and the latter pulled out for the next cast allowing, after some 14 days, the stressing cables to be inserted, tensioned and locked off.
A tandem lift plan for the 115-tonne precast deck units was used on the project, whereby each unit was transported by rotatable crane for final placement by 220 tonne and 300 tonne mobile cranes onto the available headstocks.
KiwiRail’s Reidy says it is important for New Zealand that KiwiRail becomes “a high performance organisation”.
“Our focus remains on delivering further efficiencies and making improvements in our business so we can continue to build on the growing support of our customers, increase our market share and ensure a viable and sustainable rail system for future New Zealanders. That will involve simplifying the business, standardising our assets and investing in our people.
“In 2013/14 rail removed around 1.2 million trucks from our roads, and in doing so enabled roading upgrades to be deferred and provided significant environmental and safety benefits.”
*This article was first published in August’s Contractor