The safest way to travel through the Alps
Published: 01 January, 2008
Where Hannibal crossed the Alps, the Swiss went right through them. On the 9th of December 2007, a new milestone in Europe’s high-speed rail network, the Lotzberg Base Tunnel, was opened for traffic.
One of mainland Europe’s most ambitious infrastructure projects was completed in June 2007 and was opened for traffic on the 9th of December 2007. The Lotzberg Base Tunnel – operated by BLS Alptransit – is 34.6 kilometres long and reaches from Frutigen in the Kander Valley to Raron in the Rhone Valley in Switzerland. Together with the Simplon tunnel and the to-be finished Gotthard Base Tunnel, it is part of a high-speed rail network called NRLA (New Rail Links through the Alps).
This network has been designed to alleviate the increasingly burdened Swiss road network and as a measure to connect to the European high-speed rail network.
The Lotzberg Base tunnel cost CHF 910 million (1998 prices) or £375,230 million ($750m) to build, and during the design stage the greatest operational safety was kept in mind at all time, says Walther Zumkehr, Chief Emergency Services for tunnel operator BLS Alptransit.
The tunnel is designed as a dual tube single-track tunnel. Every 333 metres there is a transverse tunnel. This ensures that one tunnel can always be used for rescue access to the other. The sliding doors that close off the transverse tunnel can be opened even under the most difficult circumstances and they are also able to withstand a fire for at least 90 minutes. In addition each tube has both a separate power supply and emergency lighting system. Every system has a duplicate in the tunnel so that if one fails operations can still continue.
Air supply
Walther explains that the ventilation system consists of two supply channels and one extractor channel based in three different air headquarters (ventilation shafts). One of the supply channels, based in the Mitholz station, delivers fresh air at a rate of 150 m3/s. The other fresh air supply channel in the Ferden station delivers air at a rate of 200m3/s. These are especially important in an emergency, as under normal circumstances the movements of the trains ensures sufficient air supply.
The exhaust air system, based at Fystertella station, will only be activated when an emergency occurs and it will extract the polluted atmosphere from the tunnel.
Walther explains that no cost was spared on monitoring and detection units. “Approximately 3,200 fire detection units are installed as well as 420 handheld extinguishers. The technical rooms, access tunnels, the official tunnel and even the drainage system and containers have fire detectors, gas detectors and moisture detectors. The technical rooms are fitted with Inergen gaseous extinguishing systems.”
The control room monitors the tunnel’s temperature and humidity via sensors. Additionally a train control system ensures that any train with a problem, such as overheated axles or a shifted load, cannot enter the tunnel.
133 video cameras are installed at all tunnel access points as well as the service and emergency stations. The images captured on the videos are transmitted via a separate data circuit to the local control centres at the North portal in Frutigen and to the South portal in Raron. Subsequently they go to the top-level control centre in Spiez.
“The largest but also most unlikely risk we face is a large fire in the tunnel. Another risk would be the escape of dangerous substances, either liquids or gases, from a freight train.”
If a fire breaks out on the Lotzberg Base line the affected train must be able to drive for at least 15 minutes in order for passengers to reach an emergency station, service station, or intervention area near the portals. During this time people on-board can’t pull the handbrakes, and the air conditioning system switches off automatically. If driving onwards is not possible, the train will try to reach the emergency stop in Ferden, where people escape via a fire proof escape tunnel and rescue personnel can evacuate them via a vehicle. If a train cannot reach Ferden, passengers and train staff have to escape via the nearest transverse tunnels into a protected area of the parallel tube and wait for assistance.
The evacuation procedures are different in each tunnel segment: in the parallel tube at the south segment this would happen by train. In the middle segment this would happen by bus and in the north segment minibuses would be used.
The automatic alarm system in the tunnel is based on different scenarios, all with their own specific code. Based on this the corresponding intervention units are deployed in co-operation with the police.
Training and organisation
The intervention staff in the Lotzberg Base Tunnel consist of teams employed by both BLS Alptransit and SBB (the rail company that operates the Lotzberg Base line), supported by the local municipal fire brigades.
“Altogether 160 firefighters and 50 supporting team members are trained by police, medical health service and other executives of the local province,” explains Walther.
The firefighting team exercises five times a year and is led through an extensive module system in which they learn how to fight fires from the designated firefighting and rescue train. The team members learn how to operate tunnel applications and related systems. They are familiarised with the local environment and are taught how to approach incidents in certain locations.
Most of the strategies applied by the tunnel fire brigade are based on the fire and rescue train; non-rail vehicles are only used in very specific cases. Because water supply is scarce in the tunnel the train is equipped with a CAFS and thermal imaging cameras. Furthermore the team are all kitted out in the latest fire protective gear.
When there is an extreme heat build-up the team has at its disposal some strategically-placed, super PPV fans. “Safety goes first,” he continues. “When the heat has built up to levels which are unsafe to operate in, and I feel that in spite of our equipment and experience it would be unsafe to continue, I would give the orders to retreat.”
Walther explains that the maximum response time to anywhere in the tunnel is 45 minutes and whilst the infrastructure belongs to the Swiss confederation, the firefighters are paid by BLS Alptransit.
Another very important factor that can greatly influence the success of fire service operations is the emergency power supply.
In the Lotzberg Base Tunnel the power supply is two-sided and should a major blackout occur, it could be switched to either side. Should something happen to the provider of the electricity then the most important tunnel functions – eg lighting – can be guaranteed for 90 minutes, powered by a battery aggregate. On top of that the fire service has mobile lighting appliances.
The firefighting team communicates via GSM-R-radionet. The fire and rescue train also has its own communication network and when all else fails there is also the option of using the wire-engaged fixed phones that have been installed every 333 metres along the length of the tunnel.
Before its official opening, BLS Alptransit focussed on constant testing and reviewing of the safety systems in the tunnel. From December 2007 onwards, the Swiss Freight Transport Authority envisages around 110 trains travelling through the tunnel every day of which 30 will be passenger trains and 80 goods trains.
Whereas in the past people might have been slightly apprehensive of travelling through the Alps, modern day technology and engineering is set to transform the face of Alpine transport.
