International contractors are being invited to prequalify for the construction of a rail tunnel under Istanbul’s Bosphorus Strait in Istanbul.

The green light was given after Turkey signed a US$104M loan agreement with the Japan Bank for International Cooperation to help finance construction of the US$840M tunnel in July.

The transportation ministry gave contractors until 17 September to register for the construction of the Marmaray tunnel and its railway stations.

Tenders should be called in December, with bids expected to be returned next April.

Construction is likely to start later in 2003 with completion due in 2008.

The tunnel is part of a larger US$2.5bn, 13.3km metro rail system in Istanbul that will improve communications between both sides of the city.