The Liverpool Overhead Railway Southern Extension Tunnel, also known as the Dingle Extension Tunnel or variations thereof, stretches for half a mile from Herculaneum Dock to Dingle underground railway station, which was the southern terminus of the Liverpool Overhead Railway.

Dingle railway station is a disused underground railway station located on the Liverpool Overhead Railway (LOR), at the south end of Park Road, Dingle, Liverpool. It was the only below ground station on the line. Trains accessed the station via a half-mile tunnel, bored from the cliff face at Herculaneum Dock to Park Road. It is the last remaining part of the Overhead railway, with the surface entrance still standing. The former platform and track area were in use as a garage called Roscoe Engineering until 2015.