these lines remain conceptual and have never been constructed. The building of the bridge coincided with the construction of a system of underground railways in Sydney's Central business district, known today as the City Circle, and the bridge was designed with this in mind. The bridge was designed to carry four lanes of road traffic, flanked on each side by two railway tracks and a footpath. Both sets of rail tracks were linked into the underground Wynyard railway station on the southern end of the bridge by symmetrical ramps and tunnels. The eastern-side railway tracks were intended for use by a planned rail link to the Northern Beaches, though they were used for tram services from the North Shore to Wynyard station. The intention was to operate tram services until the implementation of a heavy rail service to the Northern Beaches; however, when tram services were discontinued in 1958, they were converted into extra road traffic lanes, which now serve the Cahill Expressway and a city-bound bus lane. The Depression, and later World War II, along with the post-War growth of motor vehicle usage led to projected patronage of passenger services in Bradfield's plan being overestimated. Parts of the city underground were constructed and exist as the present-day City Circle. Small sections were also built for additional proposed city lines, such as additional platforms at Wynyard and St James railway stations which have never been used for heavy rail transport. In 1923, the first sod was turned on the city railway. The City Circle was constructed originally as a stub line to St James, via the Town Hall, Wynyard and towards the Harbour Bridge. It was not until 1955 that the loop was completed by the construction of Circular Quay station. A line to the eastern suburbs was eventually built, but along a different alignment to that envisaged by Bradfield, who proposed a line along Oxford Street. Bradfield retired from the New South Wales Department of Public Works at the end of July 1933 after 42 years of service with the intention of continuing to work as a consulting engineer. Other works Bradfield was the designer and consulting engineer for the Story Bridge, Brisbane. He also designed the Cataract and Burrinjuck Dams. In October 1938 Bradfield published a proposal (known as the Bradfield Scheme) for diverting some coastal rivers of Queensland onto the western side of the Great Dividing Range.