Although a crossing loop was installed at Caringbah Station and Gymea Station when the line was opened, the single track line prevented the expansion of services to the Cronulla peninsula, and so in the 1980s, it was decided to duplicate a section of the line between Gymea and Caringbah, with Gymea, Miranda and Caringbah all receiving island platforms. The new section was opened on 15 July 1985.Forsyth, J.H. (ed.) (1988–93), Stations & Tracks; Vol. 1: "Main Suburban & Branches – Illawarra & Branches". State Rail Authority of New South Wales: Sydney, p. 206. In the 2000s, the remaining single track sections were duplicated. These opened on 19 April 2010.Timetable and platform changes on the Cronulla branch line CityRail. Retrieved 4 March 2013
