Rome, July 29 - A consortium led by Italian rail-maker Ansaldo STS won a $680 million contract to build a 40.7 km metro system line in Riyadh - the Saudi Arabian capital's longest - Ansaldo STS announced on Monday. ''The contract awarded is one of the most important in our history, and demonstrates the technological excellence achieved by the company over the years,'' said Sergio De Luca, chief executive of Ansaldo STS, in the statement. ''This new contract consolidates our presence in the Middle East market, and particularly in Saudi Arabia, where we have already built, in a very short time, the country's first automated metro system, to serve the world's largest university campus,'' De Luca added. The new contract covers the construction of Line 3 - the Red Line - which will from Madina A Munawara to Amir Saad bin Abdul Rahman Al Awal Road. Under the five-year project, Ansaldo STS will serve as technology provider, while Salini-Impregilo and Larsen & Toubro are in charge of civil construction. Canadian aerospace and train-maker Bombardier will supply vehicles. The contract includes and option to pay additional $249 million for a 10 year maintenance agreement. The contract was awarded by the governor of Riyadh, Prince Khalid bin Bandar bin Abdulaziz Al Saud, who is also chair of the Riyadh Public Transport Project committee. The project is part of roughly USD six billion in contracts awarded Ansaldo STS-led consortiums, including two large rail stations, the ''Qasr Al Hokom'' and ''Western Station'', which are currently under the final design phase. Ansaldo STS is listed on the Milan bourse and 40% owned by the Italian transport and defence conglomerate Finmeccanica. Finmeccanica's shareholder of reference, with a 30.2% stake, is the Italian state.