In 1990, the
State Government called for Expressions of Interest to build a line to the airport. In July 1994, the Government announced it had entered a
public private partnership with Australian investment company
Transfield Services and French construction company
Bouygues to build the line. Under the deal, a private company,
Airport Link Company, would cover the costs of building four of the stations. In return it would operate those stations for 30 years and have the right to impose a surcharge on fares for their use. The company's involvement was predicated on passenger estimates and train reliability guarantees that later proved to be optimistic. The State Government would fund (and own) the railway itself and Wolli Creek station. At the time, the main public transport link between the city and its airport were two
Sydney Buses express routes, the 300 to
Circular Quay and 350 to
Kings Cross branded as
Airport Express. A
tunnel boring machine was used for the construction. Manufactured by the German firm,
Herrenknecht, it arrived in Australia in October 1996. While the use of a Tunnel boring machine relieved the need for large numbers of workers at increased pressure, a
caisson system is formed at the cutting head. Workers entering this space for inspection, maintenance and repair had to be trained. Medical direction was utilised for planning compression and decompression, assessment of
fitness to dive, training of workers and lock operators, health monitoring of workers and treatment of related injuries. This project was the first time
oxygen decompression tables were used for caisson work in Australia. The incidence of
decompression illness was 1 case in every 286 pressurisations (0.35%) and this problem affected 5.9% of the workers. In conjunction with the construction of the new line, the section of the East Hills Line between Wolli Creek Junction and
Kingsgrove was quadrupled. Once this was opened, the running patterns of the trains on the lines changed. The
flying junctions interchange near
Central station was altered to give the Airport line its own platforms (21 & 23) at Central. Local (all stations) trains generally were timetabled to run from East Hills via the airport, peak hour express trains from
Campbelltown run along the original route via
Sydenham, taking the express tracks between Kingsgrove and Wolli Creek Junction. == History ==