Penshurst and Mortdale. At Mortdale is the Mortdale Maintenance Depot which lies on the eastern side of the tracks with access points from the south of the station. The line then continues to Oatley which has a set of points allowing trains to be turned-back. The line then crosses the Georges River over the Como bridge, which opened in November 1972 replacing an older single track iron lattice bridge which still exists to the east of the present structure and is used as a cycleway. The line enters the Sutherland Shire, passing through Como station (which was moved to its present, new site with the opening of the new bridge in 1972), and Jannali before reaching Sutherland. At Sutherland, three platforms are provided. The Cronulla line branches off in an eastwards direction south of the station. The former short branch line to Woronora Cemetery branched in a westerly direction at the south of the platforms. The line opened on 28 July 1900 and closed on 27 August 1944. The line then continues south through Loftus, Engadine, and Heathcote. South of Loftus, the former Royal National Park line branched off, this has now been converted into a tram line connecting to the Sydney Tramway Museum, and connections to the mainline have been severed. The final station for the operation of suburban services is Waterfall station. At Waterfall, there is a train stabling yard and a train turnback (shunting road) south of the station. South of Waterfall is the site of the 2003 Waterfall train disaster. The line then heads south through the challenging terrain of the Royal National Park and Illawarra escarpment. The line makes a steep descent down to Wollongong. The original alignment through the towns of Helensburgh and Lilyvale which opened in 1888 was bypassed by a new route in 1915. A new station at Helensburgh was subsequently opened with the new alignment. A set of points allows the turnback of trains at Helensburgh. The line then proceeds through several tunnels down the Illawarra escarpment through the hamlets of Otford, Stanwell Park and Coalcliff. South of Coalcliff, the line becomes single track as it passes through the Clifton Tunnel, before becoming double track again near Scarborough station. The line then proceeds south through the northern suburbs of Wollongong, then Wollongong and its southern suburbs. A terminating platform is provided at Thirroul, which is used to terminate peak hour services