The line is one of the most scenic in New South Wales, and for the first 20 km (12 mi) after leaving Unanderra has an almost continuous grade 1 in 30 providing extensive views over the Illawarra coastline.

[2] The single track bridge at Dombarton was recycled in February 1992, being installed on the Lavender Bay branch of the North Shore line at Waverton.

However, the impetus for the line was as a condition of the erection of a new steelworks at Port Kembla, by Hoskins Iron and Steel.

[11] The line initially carried mainly limestone from the Marulan Quarry to Port Kembla Steelworks, but also vegetables from Robertson to Sydney and later, coal.

[11][12] A locomotive hauled weekend train from Sydney to Moss Vale via Unanderra was introduced and operated until July 1994.

[15][16] Initially the train operated from a base established in the Port Kembla Locomotive Depot Complex as a return Wollongong to Moss Vale service.

Steam locomotive SMR18 was leased by 3801 Limited from the Hunter Valley Training Company for the service.

Financial difficulties led to the suspension of the Cockatoo Run from November 1998 until March 1999, after which date the train ran between Port Kembla and Robertson only.