Gauge All trains in Sydney use standard gauge, with a distance of between the rails. Terminology The railways in Sydney generally use British-derived terminology. Points refers to what in American English are known as railroad switches, or crossovers. Up refers to the direction "towards Sydney", where 'Sydney' is generally defined as Central Station. Down refers to the direction "away from Sydney", or "towards the country". Signal box refers to the signal control installation (tower in American terminology). Railway lines Mainlines Four main 'trunk' lines radiate from Sydney to the north, south, west, and southwest: The Main Western railway line from Central through Strathfield and west to Penrith and western NSW. The Main North railway line from Strathfield north to Hornsby and on to northern NSW The Main Southern railway line from Lidcombe through Regents Park and Cabramatta and southern NSW The South Coast railway line (also known as Illawarra railway line) from Redfern south to Sutherland and on to Wollongong and the South Coast. Other suburban lines Other passenger lines branch from or interconnect with the four main lines: The Airport Link, an underground line linking the airport to the city. The Bankstown railway line, from Sydenham to Lidcombe via Bankstown The City Circle, a mostly underground loop in central Sydney The Cronulla railway line, from Sutherland to Cronulla The East Hills railway line, from Tempe to Glenfield via East Hills. The Eastern Suburbs railway line, a mostly underground line from Central to Bondi Junction The North Shore railway line, from Central to Hornsby via the Harbour Bridge The Old Main South railway line, from Granville to Cabramatta via Fairfield The Olympic Park railway line, a balloon loop line between Lidcombe and Olympic Park The Richmond railway line, from Blacktown to Richmond The South West Rail Link, from Glenfield to Leppington. Rapid transit lines The Sydney Metro Northwest, from Tallawong to Chatswood Includes the converted Epping to Chatswood rail link, an underground line connecting the North Shore and Main Northern lines, and serving the Macquarie Park employment area. Light rail lines Lines with light rail specifications: The Dulwich Hill Line (otherwise known as the Inner West Light Rail), from Central to Dulwich Hill. Mostly runs along a former section of the Metropolitan Goods Railway. CBD and South East Light Rail (abbreviated to CSELR) from Circular Quay to Randwick and Kingsford. The Randwick branch opened in December 2019, whilst the Kingsford