page_title: Railways in Sydney
section_title: Electrification
hierarchical_section_title: Railways in Sydney / History / Electrification
caption_attribution_description: English: Pictorial map of the underground railways proposed to be constructed in the Sydney CBD by Dr JJC Bradfield in the early 20th Century en:Commons:Category:Maps of CityRail Sydney
context_page_description: Sydney, the largest city in Australia, has an extensive network of passenger and freight railways. The passenger system includes an extensive suburban railway network, operated by Sydney Trains, a metro network and a light rail network. A dedicated freight network also exists. Future expansion of the light rail network includes the newly opened CBD and South East Light Rail, and the planned Parramatta Light Rail.
  Central station is the major terminus for Sydney Trains suburban services, while Sydney Terminal serves NSW TrainLink regional and intercity services and the Dulwich Hill Line. Great Southern Rail's Indian Pacific train service to Perth also departs from here.
  Sydney's suburban rail network is the busiest in Australia, with over 359 million journeys made in the 2017-18 financial year.
context_section_description: New South Wales uses an overhead electrification system at 1,500 volts direct current. Whilst inferior to and more expensive than modern single phase alternating current equipment, it was in vogue during the 1920s, having been used in Melbourne since 1919 and is generally sufficient for the operation of electric multiple unit trains. However, the introduction of powerful electric locomotives in the 1950s, followed by the Millennium train in 2002, revealed drawbacks in this antiquated system of electrification. As the voltage is relatively low, high currents are required to supply a given amount of power, which necessitates the use of very heavy duty cabling and substation equipment. Until the retirement of electric locomotives from freight service in the 1990s, it was often necessary to observe a "power margin" to ensure that substations were not overloaded. This situation was similar to that which applied to The Milwaukee Road's 3,000 VDC electrification. Plans to electrify the Hunter Valley at 25 kV alternating current were abandoned in the 1990s.
  Electrification came to Sydney's suburbs on 9 December 1926 with the first suburban electric service running between Central station and Oatley on the Illawarra line. In the same year, the first underground railway was constructed north from Central station to St James in Sydney's central business district. Electric trains that had previously terminated at Central station continued north, diving underground at the Goulburn Street tunnel portal, stopping at Museum station and then terminating at St James. Other lines were soon electrified. Also, in conjunction with the construction of the Sydney Harbour Bridge which opened in 1932, an additional four-track underground line was constructed from Central station to Town Hall and Wynyard. Two of the tracks continued over the Harbour Bridge connecting to the North Shore line.
  It was only in 1956 that the two tracks terminating at Wynyard were linked to the line terminating at St James via the Circular Quay viaduct. This new arrangement, dubbed the City Circle, allowed services to make a continuous run through the city and return to the suburbs without having to terminate.
caption: The original railway network for Sydney CBD planned by John Bradfield.
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