A Tunnel Through The Alps

Key Data

Country: Switzerland

Location: Swiss Alps

Project Name: Gotthard Base Tunnel

Developers: Alp Transit Gotthard AG (SBB)

Route Length: 57km (35.4 miles)

Tunnel Portals: Erstfeld, Uri and Bodio, Ticino

Gauge: 1,435mm

Summit Altitude: 550m

Power: 15kV ac overhead supply

Constructing Consortia: ARGE AGN, ARGE Transco-Sedrun, ARGE TAT

Rail Infrastructure Consortium: Transtec Gotthard

Workforce: Approx. 2,000

Tunneling Max. Speed : 40m per day

Project Cost (est. 2007): CHF11.83bn/$8 billion

Max. Speed – Passenger: 250km/h (155mph)

Max. Speed – Freight: 160km/h (100mph)

Estimated Completion: 2017

The challenge: Dig the longest tunnel ever, perfectly level, through the base of the Alps

 A cultural and trading barrier across Europe for centuries, the Alps remain so for transport. Implications have been marked in Switzerland as traffic has largely been in transit, rather than for Swiss producers or consumers. A motorway construction programme and the opening of the Gotthard road tunnel in 1980 greatly encouraged freight by road. General concern was joined by the shock of the multiple fatalities in the Gotthard and Mont Blanc road tunnel accidents.

To control adverse environmental effects, the Swiss constitution incorporated Protection of the Alps in 1994. Previously during 1992, Die Neuen Eisenbahn-Alpentransversalen (NEAT) or the New Rail Link through the Alps (NRLA) programme was approved for building two base tunnels. These were to be relatively level alignments at lower levels than previous tunnels through the massif on the BLS Lötschberg and SBB Gotthard routes.

"The base tunnel will consist of two bores with two track crossovers and multiple interconnections for foot access between the bores."

Commercial operations through the partially fitted out 34.6km (21.5 mile) Lötschberg base tunnel began in December 2007.

The project

Controls on road freight were only deemed acceptable by surrounding EU countries if better rail infrastructure was created, notably at the Lötschberg and Gotthard pinch points. Even with access to dedicated Rollende Landstrasse (RoLa) trains for transit of complete heavy goods vehicles, both north-south routes had long, slow climbs at either side of tunnels at the respective summits and capacity was limited. The NEAT projects were aimed at removing the main limiting factors for the introduction of more, faster and longer trains on the key Rotterdam-Milan rail corridor.

A 100% Swiss Federal Railways (SBB) subsidiary, AlpTransit Gotthard, was established in May 1998 to deliver the project for the 57km (35.4 mile) Gotthard Base Tunnel. Construction is split into five sections, each with a designated consortium, from the north being: Erstfeld (ARGE AGN), Amsteg (ARGE AGN), Sedrun (ARGE Transco-Sedrun), Faido (ARGE TAT) and Bodio (ARGE TAT).

Other contractors are responsible for the many other aspects of the project. As at December 2007, estimated final costs were put at CHF11.83bn, 9.59bn for the Gotthard and 2.24bn for the related 15.4km (9.6 mile) Ceneri tunnel project further south on the route. These amounts exceed the original estimates, with the Swiss parliament approving reserves for uncertainties that included geological conditions, engineering issues and technological developments, the latter relevant due to the long project timescale.

Infrastructure

Of slightly different length, the base tunnel will consist of two bores with two track crossovers and multiple interconnections for foot access between the bores. Entirely to the east of the current Gotthard line, access tracks to the new tunnel joining the present line at Erstfeld in the north and Bodio in the south. At a maximum altitude of 550m, the base tunnel is about 600m lower than the present line's summit and overall renders the Gotthard route no more challenging than many other parts of the SBB network.

To speed the project, intermediate shafts were sunk to allow for simultaneous tunnelling on several faces, these points (Amsteg, Sedrun and Faido) to become integrated in the finished structure for servicing and emergency access. Strict environmental control is in place for the work sites, the material supply chain and for the disposal of spoil.

The tunnels are mainly created by tunnel boring machines, with some use of drilling and blasting. The final section, 7.2km from Erstfeld, began in August 2007 with a target of late 2009 for breakthrough at Amsteg. Aside from the much higher speeds that the new alignment will provide, by avoiding the climbs, curves and spirals of the original Gotthard, the project will shorten the route by around 40km (25 miles).

As in the case of the Lötschberg, the old line will be retained for local passenger services, for general capacity and as a diversionary route: a noted part of railway tourism, it also provides an interchange with the east-west metre-gauge network via Göschenen.

Rolling stock

With freight most constrained by the present line and many trains needing double-heading for both the north and south ramps, an implication is a reduced need for motive power per train. Increased train lengths and weights will be possible through the near-level base tunnel, although in absolute terms the rising traffic demand will not diminish the need for freight locomotives.

Planning allows for advances in freight vehicles to allow for speeds up to 160km/h (100mph) through the tunnel. Longer trains and more of them allow for doubling the present freight capacity on the Gotthard route, much of which will be intermodal services, with Alp Transit setting the amount at around 40 million tonnes annually.

Domestic passenger services south to Chiasso and Locarno are likely to be formed in part by a next generation of Swiss coaching stock or units cascaded from elsewhere on the SBB network. Entering line testing in 2008, the ETR 610 from Alstom Ferroviaria is to become the flagship high-speed unit operating Cisalpino services between Switzerland and Italy. For Zurich-Milan, a 50min reduction to 2h50min by Cisalpino units is envisaged.

Signalling and communications

Following settlement of a legal challenge over the initial selection, the last major contract signed (CHF1.69bn in April 2008) for the Gotthard project was with the Transtec Gotthard Consortium to fit out the tunnel and approach tracks. Starting at the south portal, the work should begin in early 2009.

As installed in the Lötschberg, the Gotthard and Ceneri tunnels are to be fitted with ETCS/ERTMS Level 2 that obviates trackside signals. A leading adopter of the EC-sponsored system, non-EC Switzerland is advanced in the equipping of its rolling stock with the required equipment.

The future

By August 2008, about three quarters of the planned 153.3km of tunnels, related galleries and passages had been excavated. Two aspects of the original project have been postponed indefinitely. The Porta Alpina deep level station planned as part of the Sedrun access point was shelved in September 2007 over concerns relating to cost, value and technical issues.

The 11km second phase of the Zimmerberg base tunnel on the Zurich-Zug section has also been dropped. Becoming the world's longest railway tunnel, commercial operation of the Gotthard Base Tunnel with scheduled train services is now planned to start no earlier than the end of 2017.

Additional info : 

A Tunnel Through The Alps 7,546 feet: Most amount of rock above tunnel

26.5 million tons: Volume of excavated rock

95 miles: Total length of all tunnels and shafts

2,000: People working on the tunnel, 24 hours a day, 365 days a year

2.5 million liters: Water used per day

5 megawatts: Power required to operate one of the four tunnel-boring machines Nick Kaloterakis

source : Gotthard Base Tunnel and A Tunnel Through The Alps