Not only. I have no idea on what the project details are, but - generally speaking and if possible - building an open-cut tunnel (as opposed to bored) is much

Not only. I have no idea on what the project details are, but - generally speaking and if possible - building an open-cut tunnel (as opposed to bored) is much cheaper (like 1/3 of the cost) and much faster (also because the works are not sequential and can thus be carried on easily in multiple stretches at the same time, given enough equipment and workers ).