RESILIENT INFRASTRUCTURE Track Photo: Azvi Photo: 1RUZD\pVƬUVWslab WUDFNFRPPLVVLRQHG Construction of a long single-bore tunnel to alleviate capacity problems in the DUHDLQFOXGHGWKHOD\LQJRIWKHƬUVWEDOODVWOHVVWUDFNLQ1RUZD\

pened for traffic with the Top: Arna station ‚e 100 year old is one Arna – Fløen section had become the timetable change on has been rebuilt as of the country’s most important rail busiest single-track line in northern December 13, the 7·8 km part of the double- corridors, providing an east-west Europe, according to Bane Nor, OUlriken tunnel in western tracking project; connection between the coastal region carrying no less than 126 trains per day. is set to bring a step-change in this view looks east and the capital for both passengers and A decision was taken in 2009 to performance on Bane Nor’s Bergen towards Mount freight. Much of the line is single track, double-track the line, boring a second Line, helping to eliminate a critical Arnanipa. although there has been a steady tunnel parallel to the 1964 structure, bottleneck close to the Atlantic port programme of improvements over along with 16 connecting cross-passages city. But it also points to the future, as many years. at 500 m intervals to provide an the first implementation of slab track ‚e railway leaves Bergen through a emergency evacuation route. ‚e project on the national rail network. lengthy tunnel under the saw the first use of a tunnel boring mountain, which starts at Fløen, just machine for rail tunnel in Norway, with 1·3 km from the terminus. ‚e Fløen a 9·3 m diameter Herrenknecht TBM – Arna bore was completed in 1964, starting work from Arna in December 7KLVDUWLFOHLVEDVHGRQDQLQWHUYLHZZLWK Torbjørn shortening the railway by no less than 2015 and completing the main drive in Søderholm, 3URMHFW0DQDJHUIRU%DQH1RUpV9HVW 16 km and cutting the journey time around 18 months. A 800 m section at Midt Utbygging division; Alexej von Glasenapp , Senior %XVLQHVV'HYHORSPHQW0DQDJHU(XURSHDW3&05DLO2QH between Bergen and Arna by 40 min. the Arna end was excavated using and Javier Cabeza 6HQLRU3URMHFW0DQDJHUIRU$]YL Traffic volumes have increased traditional methods to accommodate an steadily over the years, and by 2009 the extension of the station’s passing tracks.

28 March 2021 Railway Gazette International Track RESILIENT INFRASTRUCTURE

provided by the concrete base allows loaded construction vehicles to use the ‘The main reasons for the new track without difficulty before the rails are accurately positioned and secured in tunnel were to enhance flexibility, to place. is meant that it was possible to lay the track in single-sleeper mode or increase the frequency of trains between using pre-assembled track panels. A transition zone design was %HUJHQDQG$UQDIURP|PLQWR|PLQ developed to ensure a smooth ride and to carry more freight by rail’ between the slab track in the tunnel and the ballasted tracks at each end. Torbjørn Søderholm, Project Manager, Bane Nor is consists of customised transition sleepers with special fastenings; a guard rail is also provided to reduce the risk e NKr4·6bn project has been construction and had been involved in of derailments and provide additional managed by Bane Nor’s Vest/Midt building almost 500 km of high speed safety. Utbygging division, with Project line since 1987. Director Hans-Egil Larsen and Project Highlights and challenges Manager Torbjørn Søderholm Ballastless track design Completing the tracklaying to a fairly overseeing five teams responsible for On straight sections, the slab track tight schedule posed a number of the various disciplines. was specified with a maximum depth challenges, particularly around the According to Søderholm, ‘the main of 460 mm between the top of the rail complex logistics and co-ordination reasons for the new tunnel were to and the bottom of the structural slab, required to manage the work inside enhance flexibility, to increase the compared to 770 mm for a comparable a single-bore tunnel, with only a frequency of trains between Bergen ballasted trackform. e saving of 3·4 m wide access road, given that and Arna from 30 min to 15 min, and 310 mm allowed Bane Nor and its Below: Completed several contractors were working on to carry more freight by rail. Now we contractors to optimise the design of slab track in the different disciplines at the same time. have the new tunnel available, we can the tunnel cross-section. . ese constraints demanded very refurbish the old bore, which will retain To meet the requirement, Azvi and detailed planning as well as rigorous its ballasted track. And once that is Bane Nor decided to use the Rheda Bottom: Construction performance by the teams from both completed we will have a double-track 2000® track system from PCM Rail.One. of the in-situ Bane Nor and Azvi in order to meet the section able to accommodate more is is one of the most widely used concrete slab. project deadlines. regional and inter-regional trains.’ ballastless track systems for high speed and high performance railways, having Competitive tendering been installed on more than 4 500 Bane Nor’s budget for major projects single track-km across Europe, the has been increased considerably in Middle East and Asia. recent years, and it is considering Rheda 2000® is assembled from whether to use more ballastless track prefabricated twin-block concrete in future schemes. Ballastless track was sleepers and lattice girders, concreted specified for the Ulriken tunnel, and is into an in-situ concrete base to form a also being installed on the Follobanen monolithic track structure. e B355.3 project near Oslo (RG 6.19 p49). sleepers can easily be modified to suit ‘We wanted to understand the any local requirements. ballastless track technology and benefit e use of twin-block sleepers from the know-how of experienced enables a fairly conventional installation construction companies’, Søderholm process, with the sleepers serving as a explains. ‘Our Bergen-based project temporary tie rod to keep the rails to

team realised at an early stage that it gauge during the work. e foundation Azvi Photo: was crucial to enter in dialogue with European suppliers of track systems in order to attract qualified companies to participate in the tender. A!er a prequalification phase, we usually aim at shortlisting five to seven participants for several rounds of negotiation. In general, we usually have a combination of qualitative and price elements, to be considered when evaluating the best offer. And in our case the trackwork contract UUT 31 included both design and installation of the slab track.’ A!er an extended negotiation process, Spanish construction company Azvi SAU was awarded the contract in February 2019. e Sevilla-based company had more than

100 years of experience in railway Azvi / Rail.One Photo:

Railway Gazette International March 2021 29 RESILIENT INFRASTRUCTURE Track

e project required the use of concrete ‘e Covid-19 pandemic also posed a containing synthetic fibres for added big challenge to the project over a period reinforcement, while a special frost- of about six months. Due to the new resistant concrete was used in the area regulations, foreign staff working for the close to the tunnel portal at Fløen. construction companies had to One major engineering task was the quarantine for a time when returning design and installation of a section of from a trip abroad. We were able to work floating slab track to mitigate noise and very well with Azvi to deal with this and vibration where the tunnel passes under ensure that the project could proceed the Haukeland hospital. ere is less without any significant interruptions. surface covering on the Fløen side of the ‘Bane Nor and Azvi implemented mountain, and the hospital is located just extra measures to reduce the above a 600 m long curve in the tunnel. contamination risk for the construction Azvi’s Engineering Department workers on site, and this co-operation adapted the Rheda 2000® design into a has been very satisfactory. Azvi was mass-spring system, using Pandrol able to achieve all of the specified elastomer mats under the track slab. milestones including opening the

Photo: Azvi / Rail.One Photo: e Pandrol FCA fastening system was railway on December 13 as scheduled.’ also adopted for this section, giving a total depth for the trackform of Lessons learned e main track construction Positioning of track approximately 546 mm on the outside Søderholm says Bane Nor has learned activities included the transport and components using of the canted curve. a number of important lessons from distribution of rails and sleepers along the robotic vehicle. the Ulriken tunnel scheme. ‘Having a the tunnel, pouring of the concrete Project supervision good project information management track panels, li€ing the track and Bane Nor’s construction division system is particularly important when shuttering a€er fine alignment, the worked closely with the contractors introducing multi-disciplinary projects finish concreting and flash-butt throughout the project, undertaking of this type’, he explains. ‘e T"#$% welding of the rails. 4.6 supplier audits and quality checks. ‘For Planning & Schedule so€ware helped Azvi developed two innovations for an important project like the Arna – us to estimate and calculate process the project: a robotic positioning device NKrbn Fløen line, and considering that the times and the detailed locations. e and a very precise procedure for slab track elements are fairly new to detailed planning tool adds a lot of pumping concrete. Cost of Bane Nor, we felt that it was important value in tunnel projects. As well as minimising the amount of Ulriken tunnel to visit the suppliers and sub-suppliers ‘We are currently changing our manual work, the positioning machine to ensure the highest level of quality, organisation structure to become more brought greater efficiency in the track project production processes and supply chain like a matrix. It is more and more li€ing phase. It also ensured a high considerations’, says Søderholm. important to establish best practice and level of accuracy in positioning and Health and safety were also extremely to learn from experienced teams. reduced the risk of possible errors. important. ‘We try the utmost to reduce However, with all the safety measures e concrete pumping procedure the number of accidents and to reduce needed to reduce the risk of ensured that work could meet the 7KHƮRDWLQJVODEWUDFN the risk of any incidents occurring’, he contamination during the coronavirus estimated daily performance needed to to reduce vibration says. ‘You have to bear in mind that pandemic, we had to keep the number achieve the targets. Using an experienced uses a Rheda 2000® tunnel projects are especially of physical meetings and visits to a installation team, Azvi laid an average of mass-spring system challenging from a logistics perspective, minimum. Our colleagues in other areas approximately 150 m of slab track per with Pandrol FCA and there are many movements, which and departments have been very eager day throughout the tracklaying phase. fastenings. need to be handled professionally. to learn more about our experience.’ Image: Azvi

30 March 2021 Railway Gazette International