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Rail route to regeneration

Rail Turin cross rail

Relieving crippling traffic congestion in Turin was never going to be easy.

Mark Hansford reports from a real, live Italian Job.

When in the 1969 film, Charlie Croker's gang pulled off their daring gold bullion heist with little more than British pluck and three Minis, it still needed a major international football match and Professor Simon Peach to create the traffic jam. But today, the lady-loving professor might find himself out of a job.

Because 33 years on, just a football match in front of 30,000 fans at the Stadio delle Alpi is enough to cause gridlock.

One million residents live and travel within the tight confines of the city's 17th century streets.

Yet it has no underground system and no commuter rail system, with the result that 55% of daily travel takes place by private transport.

'Our biggest problem is giving accessibility to the historical centre of town, ' explains city councillor Mario Viano. 'We needed a means of access other than car.'

Two major underground projects now under construction - a £770M north-south cross rail scheme and a £530M east- west Metro scheme - will provide these much needed public transport options.

The cross rail scheme is particularly vital, as it is central to a massive commitment by the city council to urban regeneration. For years the main railway running north-south through Turin, linking Italy to France and beyond, has represented a huge barrier between the east and west of the city.

'The railway was built at the end of the 19th century when the town centre was more to the east, ' says Viano. 'Hills limited expansion in that direction, so over the last 100 years the city has expanded west. The railway now cuts it in two.'

The cross rail scheme will see 7.5km of the railway moved underground, with two additional tracks and five new stations added for commuter trains and will allow regional trains to connect in and terminate at the main station. The space released on the surface provides the opportunity for wide, pedestrian friendly boulevards.

Juventus football club will be among those set to benefit.

Currently the nearby rail line terminates at the industrial Porta Dora in the north of the city, and with no link to the city centre, fans must travel by bus or, more likely, come by car.

When completed in 2011, cross rail trains will serve the stadium and airport from the city centre every 10 minutes.

Going underground

Turin's cut and cover cross rail scheme is effectively two projects.

The first - doubling line capacity from Porta Susa to the Lingotto exhibition centre in the south - was carried out in the 1980s, before state funds ran dry. The second - continuing the line expansion north from Porta Susa to connect with the new high speed rail link to Milan at Porta Stura (via Porta Dora) - is now under way.

The first part of this, from Porta Susa to Porta Dora (the airport link), got going in 2000 to be ready by 2005 in time for the 2006 Winter Olympics. However, a redesign called for by the city council - an extra £63M has been made available to take the railway under the River Dora rather than over it - means that the section will not open until 2007. The second section, from Porta Dora to Porta Stura, is dependent on state finance but is expected to take a further five years.

'The river tunnel will take two more years, ' explains Gianmario Cavallero, construction manager at Halferr, the engineering division of the state-owned rail operator RFI.

'But the long term advantages are more important than the delay.'

'Going over the river would have left a large chunk of the city still divided, ' adds Emanuelle Perra, of contractor Astaldi.

Cut and cover will be used for all but 350m of the 7.5km of tunnel on the 12km line with two different construction sequences.

For about half the length, where the railway is already in cutting, the sequence of work will be to install retaining walls, excavate to bottom slab level and lay bottom slab, before setting up falsework and formwork and laying a precast concrete roof.

But the preferred method, known as the 'Milan Method' after it was used successfully on the Milan Metro, is to cast the roof insitu as soon as the retaining walls are in place, before excavating beneath and laying the bottom slab. Road laying and other surface works can then begin while work in the tunnel continues.

Either way, the construction of the gallery floor remains the same.

The 2.5m by 1.8m by 350mm deep precast concrete slabs are surrounded by rubber to minimise vibration is laid between the floor slab and sleepers, and between the sleepers and the rail.

Metro countdown

Tunnelling starts this month on Turin's new metro.

As the new backbone of the city, the route of Metro Line 1 has been carefully planned to follow the two routes that carry the highest traffic volumes. Almost 30,000 vehicles enter the city daily from the south east with another 50,000 coming from the west.

Section one is now under way, with sites spaced every 700m on as work begins on service diversion and excavation for the stations.

The 9.6km section - from the Collegno in the west to Porta Nuova (see map p37) includes 15 stations and will cost £414M. It is scheduled to open in 2005, just months before the start of the 2006 Winter Olympics.

The seven station 4.5km second section - from Porta Nuova to the Lingotto exhibition centre in the south of the city - will cost a further £120M and is scheduled to open in 2008.

Trains will be fully automated, using a system similar to that in use on Metro systems across France. Pneumatic wheels will reduce braking distances and provide better grip for faster acceleration, allowing trains to reach speeds of up to 80km/h between the closely spaced stations. Pneumatic wheels also generate less vibration and increase the tolerances for the tunnel construction.

The trains will be small - a maximum of four, 110 person capacity cars - but at a frequency of up to one train every 69 seconds, 15,000 passengers can be carried every hour. The 9.6km journey from Collegno to Porta Nuova will take 16 minutes.

The average depth of the tunnel is 18m below street level, dipping to 25m where it passes beneath the cross rail scheme. As a result earth pressure balance tunnel boring machines will be used for the majority of the work, with stations constructed by cut and cover.

With completion ahead of the Olympics critical, three 600t Lovat TBMs will operate 24 hours a day, seven days a week, with the first started from Collegno on 5 October.

The internal diameter of the tunnel is 7.6m, and each TBM is scheduled to race through the fluvial soil at an average of 10m/day.

INFOPLUS www. oct. torino. it

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