Design operations are in demand at Fläkt Woods after winning its largest ever single contract, the project worth more than €7 million is to supply ventilation fans for the massive Marmaray tunnel rail project in Turkey

The contract will supply the air movement needs on one of the world’s biggest transportation infrastructure schemes, the 13.6km (8.5 miles) Bosphorus crossing. It has been described as the project of the century, and the tunnel will connect two continents with the €1.9bn rail-tunnel running deep beneath the Bosphorus Straits.

The tunnel consists of a series of earthquake-proofed immersed tubes, assembled from 11 sections, each as long as 130m and weighing up to 18,000 tons. These will be placed down to 60 metres below sea level; making it will be the world's deepest undersea immersed tunnel tube.

The Colchester Company is supplying a range from their super-powerful Axial fans for eight shafts ventilating the new crossing. Measuring up to 2.8m in diameter, the fans will be capable of providing emergency ventilation in the worst-case scenario, a fire on a freight train more than a kilometre long.

The specialist fans generate a relatively high velocity discharge of air-flow through the tunnel. As the jet from the fan diffuses, it transfers energy to the tunnel airflow and creates an increase in static pressure, which causes air to flow as in any conventional system.

Paul Wenden, the Company’s engineering and marketing director, said: “We export half of what the Colchester factory produces, and our ability to diversify, sourcing business in both the building and infrastructure and industry markets, has helped us to find new business and this contract is a great example of this.”

Additional underground stations will be constructed at 3 locations, and 37 new above-ground stations will be rebuilt or refurbished. Once it is operational, the new transport link is likely to attract more than 1.5 million passengers using the tunnel per day.