OSLO, August 19, 2008 (AFP) - Norway's public railway company NSB announced Tuesday it had ordered 50 passenger trains from Switzerland's Stadler worth 4.0 million kroner (502.5 million euros, 736.9 million dollars).

'This is the largest single contract ever signed by NSB and a historic decision,' company chief Einar Enger said in a statement.

NSB said the 50 Stadler Flirt train sets, each counting five carriages and with a maximum speed of 200 kilometres (124 miles) per hour, would be delivered in 2012.

The contract also gives the Norwegian company the option to purchase an additional 100 train sets.

According to Norwegian media reports, Siemens of Germany had been expected to win the contract.

'We considered a number of elements (including) technical function, delivery ability, price and environment,' NSB project leader for new trains Emil Eike told AFP.

'Stadler came out on top,' he added.

The additional 14,000 seats NSB will gain with the new Stadler trains are expected to help it achieve its stated goal of doubling its passenger numbers over the next 20 years.

The Stadler Flirt trains are built to withstand a Norwegian climate and are already in use in a number of countries, including Switzerland, Germany, Austria, Algeria, France and Finland, NSB said.