The original Port Dock station was closed in 1981, with part of its site later repurposed for the National Railway Museum.

The loop was cut when rail freight moved off the broad-gauge Outer Harbor railway to the nearby standard-gauge line on the eastern side of the peninsula.

A 2016 report into potential light rail projects in Adelaide considered two options for the future of the line.

[8] The spur line and a new Port Dock station, after several delays and costing increases, were opened in September 2024.

[11][12] In 2024, transport minister Tom Koutsantonis flagged another possible electrification and an extension of the line to accommodate workers at the Australian Submarine Corporation at Osborne.

The outcome was to make the Gawler trains use the central pair of tracks, while the Outer Harbor line now uses the eastern pair across the bridge, then descends into a trench and passes underneath the Gawler and standard gauge lines and Park Terrace which had previously been a busy level crossing.

The northern section of the line runs along the middle of the narrow Lefevre Peninsula with stations at regular intervals.

[23] During special events, such as AFL matches, Adelaide Metro will typically run extra Osborne services.

[24] As Outer Harbor railway station is in close proximity to the Port Adelaide Passenger Terminal, the Outer Harbor line is regularly utilised by cruise ship passengers during the summer cruise season.