Replacement of the Siagne Viaduct: a challenge overcome

The replacement of the Siagne Viaduct was carried out in 132 hours without interruption, from 25th to 31st October. This particularly large railway project involved one of the biggest cranes in Europe to enable the shifting of the new viaduct to replace the old one. The previous viaduct, opened in 1862, limited trains to a crossing speed of 40km/h due to its age.

Working for SNCF Réseau, the organisation that operates France’s rail network, SYSTRA provided project management assistance and general project management covering the entire modernisation of the viaduct and feasibility studies right up until the opening of the new viaduct. In this role we supervised the construction of the new 82-metre viaduct deck on the site, before it was placed on driven piles in the river and shifted track by track. Since the project’s completion, and the resumption of train traffic on the morning of 31st October, trains can once again cross the Siagne at 140km/h, notably on the regional express train line (TER) that connects Marseille, Toulon, Cannes, Menton and Ventimiglia, linking France and Italy.

Wassim Kanso, SYSTRA project manager responsible for the operation in the Project Management Operations Department (DMO), commented: “This viaduct replacement is a unique project and we were fully committed at every stage to our client SNCF Réseau. The complexity of this assignment was in the numerous interfaces that had to be managed to enable the new infrastructure to open in good time, whether civil engineering, track, catenary or administrative procedures due to the viaduct’s protected surrounding environment. I am very proud indeed as everything went smoothly. For me this represents the end of four years of hard work.”

Record-breaking achievement

Following the launch of preparatory works in April 2017, assembly of the new viaduct started in October 2017 and finished in February 2018. Each deck weighs 660 tonnes and the installation necessitated pouring 270m3 of concrete. Two impressive cranes were used: a steel joist crane on the right bank and a self-propelled crane weighing 800 tonnes on the left bank. The progressive shifting was done day and night at 5km/h, after the old infrastructure was lifted. The operation and all the teams involved were praised by Patrick Jeantet, CEO of SNCF Réseau.

In addition to the Siagne Viaduct, SYSTRA has led project management assistance assignments for four railway bridges and another viaduct. Now modernised, the Marseille-Ventimiglia line, built in the second half of the 19th century, is once again ready to effectively link the French and Italian railway networks.

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