Lo scavo della nuova galleria ferroviaria dell'Albula, nei Grigioni, è iniziato oggi, lunedì, dopo 14 mesi di lavori preparatori. Il progetto da 345 milioni di franchi, non privo di incognite di natura geologica, sarà ultimato nel 2020.
Il nuovo tunnel lungo 5,86 chilometri correrà parallelo a quello vecchio e in cattivo stato. L’attacco alla montagna tra Preda e Spina, a 1'800 metri di altitudine, avviene all’interno di un'enorme caverna realizzata nella roccia, a ridosso di una zona geologica poco stabile. Bisogna avanzare con tecniche particolari perché se si usassero quelle tradizionali la parete crollerebbe e il tunnel si riempirebbe di acqua e fango. Proprio come successo il 29 luglio 1900, quando, durante la costruzione della galleria storica, 16 minatori persero la vita e i lavori furono sospesi.
L'allacciamento del nuovo traforo, nel quale i convogli potranno circolare a 120 all’ora, alla rete della Ferrovia retica è previsto nel 2021. In seguito il vecchio tunnel sarà trasformato in cunicolo di sicurezza. Fino alla fine dei lavori a Preda sarà visitabile un info-centro in grado di soddisfare ogni curiosità sui lavori in corso nella montagna tra l'Engadina e le valli del centro dei Grigioni.
Diem/TG
Dal TG20
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