Rail to Cronulla dates back to 1911, when a steam tram line between Sutherland and Cronulla opened for passenger service. This single track service operated until 1931.
Construction on the current heavy rail line began in 1936 and was completed in 1939. As with all new suburban lines since electrification was begun, this line was electric from day 1. Like the tram line before it, this was also a single track line, with passing loops at Gymea and Caringbah. It would eventually be extended to dual track, first between Gymea and Caringbah in 1985, and then the rest of the line in 2010 as part of Cityrail’s Clearways project.
Interestingly, Cronulla station itself retains only a single platform, but one that has capacity for 2 trains. One half of the platform is designated as platform 1 and the other half designated as platform 2. It is designed so that trains can arrive and depart from each of these two “platforms” independently of each other. This is unique to Cronulla station in the suburban cityrail network.