The dam flooded the gorge, through which the line ran, to form Lake Dunstan.

The Dunedin Railways (formerly known as Taieri Gorge Railway) line officially begins at the 4 km peg and shortly thereafter passes around a horseshoe curve at the foot of the Salisbury bank and begins a climb at 1 in 50 to the summit at 145 m, where it passes through the 437 metres (1,434 ft) long Salisbury Tunnel, the longest on the line.

After a second tunnel, the railway runs along Mullocky Gully, crossing it over the 197 metres (646 ft) long Wingatui Viaduct, before joining the Taieri Gorge.

Wingatui Viaduct has been the largest wrought iron structure in New Zealand since it was built in 1887 and is the longest and tallest (47 m) bridge on the line.

After Flat Stream Viaduct, the aptly named "The Notches" section also presented an engineering challenge, accomplished via three short bridges and cuttings through several rocky outcrops.

On the remaining line between Wingatui and Middlemarch, passing loops exist at North Taieri and Parera, service sidings at Mt Allen, and both passing loops and sidings at Hindon, Pukerangi and Middlemarch.

DH class diesel-electric locomotives were introduced on the line in February 1957 running as far as Clyde.

The DH and DG engines were too heavy to run on the lighter rails of the Cromwell Gorge but the much lighter DJ class diesel locomotives (with 10.3 tonne axle loading) were allowed to run through to Cromwell.

With the introduction of these locomotives on 26 February 1968 the remaining AB class steam engines were withdrawn.

After the line to Middlemarch was taken over by Dunedin Railways (previously Taieri Gorge Railway and originally the Otago Excursion Train Trust) in 1990, their trains have primarily been operated by their fleet of six DJ class locomotives.

[5] The remainder of the line was lifted and the trackbed developed into the Otago Central Rail Trail.