Eastern Suburbs & Illawarra Line

The Eastern Suburbs & Illawarra Line (numbered T4, coloured azure blue) is a commuter railway line on the Sydney Trains network in the eastern and southern suburbs of Sydney. The line was constructed in the 1880s to Wollongong to take advantage of agricultural and mining potentials in the Illawarra area. In March 1926, it became the first railway in New South Wales to run electric train services.

Today, the railway consists of three connected lines:

• The original Illawarra line from the Sydney CBD to Waterfall
• The Cronulla line from Sutherland to Cronulla, which opened in 1939 replacing an earlier tram service
• The Eastern Suburbs line from the Sydney CBD to Bondi Junction, which opened in 1979

Operationally and historically, the entire line from the Illawarra Junction at Redfern to its terminus in Bomaderry on the South Coast was known as the Illawarra Line. However, since 1989, the suburban services to Waterfall and Cronulla have been marketed as the Eastern Suburbs & Illawarra Line and interurban services south to Wollongong and Bomaderry as the South Coast Line. The line is coloured an azure blue on Sydney Trains timetables and other promotional materials.