Innovative method of rail tunnel refurbishment

Private Railway organizations, like Rhaetian Railway (RhB), operate more than 50 km of tunnels aged more than 100 years. Refurbishment of those tunnels has to happen during the short period of night break. RhB developed a standardized system and tested this at Hagerbach Test Gallery to prove the concept and eliminate weaknesses before applying the system at their tunnel net. The main idea is to decentralize the working process by prefabrication of elements - a kind of segmental lining - which will be put in place during the night break. Also the machinery equipment to handle all the operations had have to be developed to realize an effective and mobile equipment which makes the maximum use of the night break. About 9 m tunnel lining can be refurbished per night with this procedure. For the evaluation process Hagerbach Test Gallery excavated a section of 40 m of tunnel with the shape of an old narrow railway tunnel. In this section the cycle of the refurbishment of tunnel composed of the steps removing the existing lining, temporary support, installation drainage, preparing for placing of elements, the placing of the elements itself and backfilling them was tested and trained with the contractor who will do the work.