    the city circle is a system of largely underground passenger railway lines located in the central business district of sydney, australia, that make up the heart of the sydney passenger railway network. the lines are owned by railcorp, a government agency of the state of new south wales, and operated under transport for nsw's sydney trains brand. despite its name, the city circle is of a horseshoe shape, with trains operating in a u-shaped pattern. the constituent stations of the circle are (clockwise): central, town hall, wynyard, circular quay, st james, museum and back to central. ==history and description==   the original concept for the city railway was part of a report dated 1915 submitted to the government by john bradfield upon his return from overseas study,50 years â a long time wylie, r.f. australian railway historical society bulletin, june 1971 pp140-143 with work commencing the following year. the city circle was built in stages. the first stations to open were museum and st. james, which opened in 1926 as part of the initial electrification of sydney railways. next was the "western limb" through town hall and wynyard, which opened in 1932 in conjunction with the opening of the sydney harbour bridge. this section contains four tunnels. two connected to the harbour bridge, while the two city circle tunnels 
Railway_lines_in_Sydney Railway_lines_opened_in_1956 Railway_loop_lines Railway_tunnels_in_New_South_Wales Standard_gauge_railways_in_Australia Underground_rapid_transit_in_Australia