Engineering

3263 HP anti-smoke fan in longest rail tunnel

What happens if there’s a fire in the longest railway tunnel in the world? Then, fans jump on that are as strong as four formula-1 cars. There is 3263 HP availible to remove all smoke from the tunnel in seconds.

How to prevent in the 57 km long Gotthard Base Tunnel in case of fire from becoming the death trap? The designers have built in Faido and Sedrun, at km 18 and 36, about two emergency stops. There can train passengers to escape a fire in safe areas, in the four air supply fans with the 1.5 MW of power per second, each 275 m3 blow fresh air.

The four exhaust fans which suck with up to 400°C hot gases from the emergency stop is even stronger. For comparison: 2.4 MW is equal to 3263 HP, that is to say an exhaust fan has the power of four formula 1 cars. The development of the 603 employees from the TLT Turbo this unit is very effective and test-run shows how quickly all controlled smoke was removed.

Over frenzied trains: fans automatically adjust to pressure conditions

Experts in the tunnel expect temperatures of 45°C in normal operation. The problem: Max 40°C are allowed for the railway. That’s why 24 so-called jet fans used, enabling the entire column of air in the tunnel in movement come in the tunnel.

Foto: AlbTransit Gotthard AG
In Faido and Sedrun, at km 18 and 36, there are emergency stops. Here are eight great axial fans used that derive from gases in case of fire and lead to fresh air. You have each 3.263 HP. Photo: AlbTransit Gotthard AG

The engineers had to take account of the special aerodynamic conditions in the train tunnel. As trains up to 250 km/h fast, was the danger that pressure shocks damaging the devices. Engineers have therefore integrated a so called pumping border alert facility, the pressure conditions in the tunnel measures ten times per second. The pressure changes with an over speeding train the fans automatically adjust the angle of attack of the blades. This prevents the fan wheels due to high acceleration to suffer damage.

gotthard-tunnel
Gotthard Tunnel, photo: wikipedia

“Differently than otherwise at the orders of the tunnel here no standardized fans are practically catalog goods, were used, but’s prototypes were developed, tested, installed and put into operation,” says Andreas Kuhn, project manager at the Gotthard Base Tunnel project.

Gotthard Base Tunnel resume as working on December 11

The solemn inauguration of the Gotthard Base Tunnel was on June 1, 2016, the operation is to start on December 11. Then the travel time between Zurich and Milan to one hour is shortened to two hours and 40 minutes. Also the freight should be more efficient. Because the route has no significant climbs, freight trains can waive the time-consuming pairing of an extra locomotive.