EIFFEL POWER: A number of steel viaducts are also being built by French firm Eiffel along the route of the TGV. A six span 155m viaduct is one of several steel structures currently under construction to the north of Avignon. Two 1.45m deep box sections have been launched. The 550m long Saint Genie viaduct crosses a deep valley and railway line before directly connecting with a short tunnel. The steel beam and concrete composite structure is in three sections; one of seven spans over 296m, one five spans over 208m and a shorter single span of 42m. Concrete piers support the top deck, which contains 1,810t of steel.