This is a formwork for the lining both of the bored tunnel and the cut-and-cover tunnel. In both cases, along the tunnel route, there are areas where the tunnel section expands laterally (sidings).

The cut-and-cover tunnel would be carried out in two phases; the first one with the concreting of the cut-and-cover tunnel itself, through the inner-outer formwork and a larger bored inner section than that of the tunnel; and afterwards, the cut-and-cover tunnel would be lined in order to achieve the same finish and section as that of the bored tunnel.

This is a formwork for the lining both of the bored tunnel and the cut-and-cover tunnel. In both cases, along the tunnel route, there are areas where the tunnel section expands laterally (sidings).

The cut-and-cover tunnel would be carried out in two phases; the first one with the concreting of the cut-and-cover tunnel itself, through the inner-outer formwork and a larger bored inner section than that of the tunnel; and afterwards, the cut-and-cover tunnel would be lined in order to achieve the same finish and section as that of the bored tunnel.