Daylighting (tunnels)


Daylighting a tunnel is to remove its "roof" of overlying rock and soil, exposing the railway or roadway to daylight and converting it to a railway or roadway cut. Tunnels are often daylighted to improve vertical or horizontal clearances—for example, to accommodate double-stack container trains or electrifying rail lines, where increasing the size of the tunnel bore is impractical.

List of daylighted tunnels