Marti, the infrastructure provider, has produced new tracked modules for SBB (Swiss Federal Railways) that will ease urgently-needed repairs to three tunnels on CFF Line 224/Lot 3 Neuchatel-La Chaux de Fonds.
Maximizing production rates and giving better safety to workers and operatives has been the aim to design the two construction trains. Currently, they are in use on the renovation of Swiss Federal Railways tunnels; 1,354m Mont Sagne, 3,259m Tunnel Mont Sagne and 254m Tunnel Combe Convers between La Chaux-de-Fonds and Neuchâtel.
Geology along the line includes Jura rocky chain – the result of the folding of Mesozoic marl-limestone strata. The limestone sections are karstic, fractured and are potential aquifers.
In the first phase of construction which is going to last until the end of Feb. 2021, the work will include mechanical removal and systematic cutting to remove sub-profile areas, plus anchoring work to secure brick vaults. Furthermore, phase two will see the elimination and replacement of the vaults with shotcrete and it is expected to have it completed at the end of 2021. Other work will comprise the excavation and support of additional niches and tunnel widening near portals using pipe umbrellas.
The works that are going to be undertaken during evening line closures, are projected to consume 113t of steel lattice girders, 20,000t of shotcrete and over 10,000m2 to be waterproofed.
Marti NE-CF Consortium – comprising Marti Tunnel and Marti Travaux Spéciaux – is undertaking the work which is expected to have it completed by April 2022.