The Airport line is a suburban railway line in Perth, Western Australia, which is operated by the Public Transport Authority as part of the Transperth system. The Airport line is a branch of the Midland line and runs underground between Bayswater and High Wycombe via Perth Airport. The branch is long and has three stations: Redcliffe, Airport Central, and High Wycombe stations. Airport line services continue west of Bayswater along the Midland and Fremantle lines via Perth station to terminate at Claremont station.
Known during construction as the Forrestfield–Airport Link, the line was constructed by a joint venture between Salini Impregilo and NRW. Construction started in November 2016 and tunnel boring started in July 2017. The construction process was beset by several problems, including ground disturbances caused by tunnelling, a sinkhole and groundwater leak during the construction of a cross-passage, several worker injuries, and poor work conditions. Tunnel boring was completed in April 2020, which was followed by the installation of overhead line equipment, tracks, and other equipment. In addition to the main contract, works included a turnback siding at Claremont station for Airport line trains to turn around, and upgrades to Claremont and Bayswater stations. Originally planned to open in 2020, the project was delayed several times due to the aforementioned problems and later supply chain issues caused by the COVID-19 pandemic; it eventually opened on 9 October 2022. The Forrestfield–Airport Link cost A$1.86 billion in total.
Transperth B-series trains, three cars in length, operate on the Airport line every 12 minutes during peak and every 15 minutes outside peak and on weekends. All Airport line branch stations are fully accessible and have long platforms; train lengths are limited by most Midland and Fremantle line stations, which have platforms only long. The installation of communications-based train control by 2027 will allow frequencies to increase and planned platform lengthening will allow train lengths to increase. In the year to June 2026, the Airport line had 6,229,613 boardings.
History Proposals
The 2004 Perth Airport master plan proposed a light rail spur off the Midland line between Bayswater and Ashfield stations, travelling above ground parallel to Tonkin Highway and along Brearley Avenue to the domestic terminal (terminals 3 and 4) and underground to the international terminal (terminals 1 and 2). The Midland line between Bayswater and Perth would have been a shared light rail and heavy rail corridor, and there would have been new stations at Great Eastern Highway, the domestic terminal, and the international terminal. The state government started planning for this, having applied to Infrastructure Australia for federal funding.
Following the 2008 state election, the new Liberal government withdrew the application to Infrastructure Australia, with Premier Colin Barnett saying that he believed airport rail links were not viable in cities the size and density of Perth. The Public Transport Authority (PTA) nonetheless continued planning for the rail extension to the airport. Planning focused on building the line above ground between the Midland line at Bayswater and the Airport alongside Tonkin Highway, before tunnelling under the airport and emerging on the eastern side at High Wycombe.
In September 2012, the government announced the half tunnelled, half above ground heavy rail line as its preferred route and said it was looking at costing and when the Airport line would be built. In December 2012, the Labor opposition announced its Metronet plan to rapidly expand Perth's rail network, which it would take to the 2013 state election in March. This plan had the Airport line as part of a loop line which would connect to the Armadale line, Mandurah line and Fremantle line to the south and the Midland line to the north. The opposition revealed further details of its proposed route, making it follow a fully above-ground route, requiring going around the airport's runways. This would have made the Airport station far away from the international terminal, requiring a shuttle bus between the station and terminal. The Labor Party costed the route at A$731.5 million, but Treasury costed the route at $1.446 billion.
In February 2013, the government committed to its own plans of building the Airport line by 2018 at a cost of $1.895 billion. The 2013 election resulted in the government's re-election, so the half tunnelled route entered further planning. By the end of 2013, Transport Minister Troy Buswell said he was considering making the Airport line entirely underground from Bayswater to High Wycombe as it could be better value for money. Transport expert Peter Newman and Opposition Leader Mark McGowan criticised the idea of building the line entirely underground, saying it would be far more expensive.
Forrestfield–Airport Link In August 2014, it was announced that the project, now known as the Forrestfield–Airport Link, would be fully tunnelled instead of only tunnelled within the vicinity of the airport. According to the government's modelling, there was little difference in the cost between tunnelling the whole route versus a partially tunnelled route; the government was in favour of the wholly tunnelled route because it would be less disruptive. State Cabinet approved the project in the same month and the project definition plan was published. The Forrestfield–Airport Link involved building twin-bored tunnels from the Midland line at Bayswater to High Wycombe, passing under the Swan River and Perth Airport. There were three stations along the route: Airport West near terminals 3 and 4, Consolidated Airport near terminals 1 and 2, and Forrestfield. Airport West and Forrestfield stations were planned to have bus interchanges. Airport West and Consolidated Airport stations were planned to be underground. It was forecast the link would have 20,000 boardings per day upon opening, increasing to 29,000 by 2031. The Airport line service was planned to interline with the Midland line west of Bayswater, passing through Perth station before interlining with the Fremantle line to Daglish station, where Airport line trains would terminate and turn around. It was estimated to cost $2.2 billion, approximately $300 million more than promised in 2013, and open in 2020, two years later than promised.
For the section between Bayswater and the Airport, three options were considered: elevated rail, cut-and-cover tunnels, and deep level bored tunnels. Bored tunnels were chosen as they reduced disruption at ground level during construction and result in less land being taken up by rail infrastructure. The tunnels were chosen to have a diameter of and have an average depth of below ground level. The maximum depth is where the tunnels cross under the Swan River. The Forrestfield–Airport Link is the second time that tunnel boring machines (TBMs) were used in Western Australia, the first being the construction of the William Street tunnel under the Perth central business district in the mid-2000s for the Mandurah line. The Forrestfield–Airport Link was planned to begin construction in 2016 and open in 2020.
In late 2014, the project was referred to the state's Environmental Protection Authority (EPA) and the federal Department of Agriculture, Water and the Environment for environmental approval. Because part of the project is on Perth Airport land, federal environmental approval was sought. The EPA approved the project in July 2015, and the Department of Agriculture, Water and the Environment determined that the project did not require assessment and approval from the federal government. State Parliament passed legislation in October 2015 authorising the Forrestfield–Airport Link's construction.
Procurement Expressions of interest to build the Forrestfield–Airport Link opened in January 2015 and closed two months later; five consortia submitted expressions of interest. In April 2015, three consortia were shortlisted: JHL Joint Venture (Leighton Contractors and John Holland), SI-NRW Joint Venture (Salini Impregilo and NRW), and Forrestfield Connect (Acciona, BAM and Ferrovial Agroman). SI-NRW Joint Venture was selected in February 2016, and in April 2016, the contract was signed for $1.176 billion. Salini Impregilo held an 80 percent stake and NRW a 20 percent stake. The contract covered construction and maintenance for ten years. Upon the signing of the contract, it was announced that Airport West station had been renamed Belmont station, and Consolidated Airport station had been renamed Airport Central station. Weston Williamson and GHD Woodhead were appointed by SI-NRW as the designers of the three stations. Other contracts included a $31 million one with Georgiou Group to build an elevated walkway between Airport Central station and the airport terminal, awarded in late 2018, and a contract extension with Downer EDI–Bombardier Transportation for the construction and maintenance of ten Transperth B-series trains. The total approved budget was $1.861 billion, of which, $490 million was funded by the federal government.
Infrastructure Australia released their assessment of the Forrestfield–Airport Link in September 2016, rating it as a "priority project" and giving it a benefit–cost ratio of 1.4. The projected economic benefits of the project were $2.372 billion.
Construction Site establishment at Forrestfield station began in September 2016, with the aim of getting the TBMs launched as soon as possible. On 3 November 2016, a sod turning ceremony took place at Forrestfield station with Premier Colin Barnett, State Transport Minister Bill Marmion, Federal Minister for Urban Infrastructure Paul Fletcher and Federal Minister for Infrastructure and Transport Darren Chester, which marked the start of construction for the Forrestfield–Airport Link. Following the Labor Party's victory in the 2017 state election, the Forrestfield–Airport Link was incorporated into the Metronet program.
Construction at Airport Central station began in May 2017.
Tunnelling
The components for the first of two tunnel boring machines (TBMs) arrived in Perth in May, having been assembled in China by Herrenknecht. The machines each cost $20million, weighed , and had a cutterhead diameter of . Due to varying ground conditions, they were variable density TBMs, a new technology at the time. The first half of the route, from Forrestfield to Redcliffe, used the TBMs in slurry mode. The second half of the route, from Redcliffe to Bayswater, used the TBMs in earth pressure balance mode. Salini Impregilo wanted to use an earth pressure balance TBM, but the Public Transport Authority required the use of a variable density TBM due to the risks of tunnelling under the airport runways without a slurry TBM and the variable geology of the alignment. A competition was launched in April 2017 for schoolchildren to determine the names of the two tunnel boring machines (TBMs). The winning TBM names were announced in June: Grace, after a primary school student with leukaemia, and Sandy, after the sandgroper, a type of insect and a colloquial demonym for Western Australians. Artwork on each TBM by local primary school students was unveiled as well.