Airport line, Perth

Airport line
High Wycombe dive structure
Overview
Other name(s)	Forrestfield–Airport Link (branch; during construction)
Owner	Public Transport Authority
Locale	Perth, Western Australia
Termini	High Wycombe (east) Claremont (west)
Stations	3 (branch) 20 (total)
Website	Forrestfield–Airport Link
Service
Type	Suburban rail
System	Transperth
Operator(s)	Transperth Train Operations
Depot(s)	Claisebrook railcar depot
Rolling stock	Transperth B-series trains
Ridership	4,860,015 (year to June 2024)
History
Commenced	3 November 2016 (2016-11-03)
Opened	9 October 2022 (2022-10-09)[a]
Technical
Line length	8.6 km (5.3 mi) (branch) 25.2 km (15.7 mi) (total)
Number of tracks	2
Character	Underground and at-grade
Track gauge	1,067 mm (3 ft 6 in) narrow gauge
Electrification	25 kV 50 Hz AC from overhead catenary and overhead rail
Operating speed	130 km/h (81 mph)
Signalling	Fixed block signalling
Train protection system	Automatic train protection
Route map Legend km 16.0 High Wycombe 00.0 High Wycombe stowage 16.0 High Wycombe 00.0 00.0 Dundas Link Abernethy Road Affleck Road Horrie Miller Drive 13.5 Airport Central Horrie Miller Drive Perth Airport runways Miller Road Woods Road Taplin Road Snook Road Ross Drive Brearley Avenue Dunreath Drive 10.8 Redcliffe First Street Great Eastern Highway Tonkin Highway Swan River Dunstone Road Guildford Road 00.0 Midland line Morley-Ellenbrook line 06.7 Bayswater Bayswater Bridge Hotham Street Bridge 05.5 Meltham 04.5 Maylands Seventh Avenue Bridge Third Avenue Bridge 00.0 03.2 Mount Lawley Guildford Road underpass 01.9 East Perth 00.0 East Perth Terminal 01.9 East Perth 00.0 00.0 East Perth tunnel Graham Farmer Freeway 00.0 Armadale line 01.3 Claisebrook Claisebrook depot Claisebrook shunting neck Lord Street Bridge 00.9 McIver Perth turnback Barrack Street Bridge Mandurah line 00.0 Perth 00.0 Yanchep line 00.0 00.0 Perth City Link tunnel James Street bus bridge Yanchep line Mitchell Freeway West Perth Subway 1.6 City West Leederville Cutting Loftus Street bridge Hamilton Street bridge 2.7 West Leederville West Leederville football platform 00.0 00.0 Haydn Bunton Drive bridge Subi Centro tunnel 3.7 Subiaco 5.0 Daglish Daglish turnback Nicholson Road subway 5.9 Shenton Park Shenton Park Bus Bridge Nagal Pass 07.4 Karrakatta 8.0 Loch Street Ashton Avenue bridge 8.6 Showgrounds Shenton Road subway 9.3 Claremont Claremont turnback 1 Stirling Road subway Claremont turnback 2 00.0 Fremantle line Railways in Perth Airport Armadale Fremantle Mandurah Midland Thornlie Yanchep List of Transperth stations This diagram: view talk edit

The Airport line is a suburban railway line and service in Perth, Western Australia, 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 Airport line branch is 8.6 kilometres (5.3 mi) 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.

The Airport line was known during construction as the Forrestfield–Airport Link. It was constructed by a joint venture between Salini Impregilo and NRW at a cost of A$1.86 billion. 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 criticism over work conditions. Tunnelling was completed in April 2020, so the installation of overhead line equipment, tracks, and other equipment followed that. Works other than the Forrestfield–Airport Link included constructing a turnback siding at Claremont station for Airport line trains to turn around, and upgrades to Claremont and Bayswater stations. The Airport line was originally planned to open in 2020, but that was delayed several times due to the aforementioned problems and later supply chain issues caused by the COVID-19 pandemic. The line opened on 9 October 2022, over two years late and $20 million under budget.

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 150-metre (490 ft) long platforms, long enough for a six-car train. Train lengths are limited by most Midland and Fremantle line stations, which have platforms only 100 metres (330 ft) 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. The line was forecast to have 20,000 boardings per day upon opening, but six months after it opened, the Airport line has 12,000 boardings per day. In the 2023–24 financial year, the Airport line had 4,860,015 boardings.

The yellow northern route is the light rail route proposed in the 2004 Perth Airport master plan.^[1] The red southern route is the route proposed by the Labor Party in 2013.^[2] The route and station locations as constructed are visible on the basemap

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.^[1] The Labor state government in the 2000s started planning for this, having applied to Infrastructure Australia for federal funding.^[3]

Following the 2008 state election, the new Liberal government withdrew the application to Infrastructure Australia,^[3] 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.^[4][5]

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.^[6][7] 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.^[8][9] The opposition revealed further details of its proposed route, making it follow a 10.5-kilometre (6.5 mi) fully above-ground route, requiring going around the airport's runways.^[2] This would have made the Airport station far away from the international terminal, requiring a 1 kilometre (1 mi) shuttle bus between the station and terminal. The Labor Party costed the route at A$731.5 million,^[10] but Treasury costed the route at $1.446 billion.^[11]

In February 2013, the government committed to its own plans of building the Airport line by 2018 at a cost of $1.895 billion.^[12][13] 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.^[14][15]

Cabinet approved the project, now known as the Forrestfield–Airport Link, in August 2014.^{[16][17][18][19]} The Forrestfield–Airport Link involved building twin-bored 8.5-kilometre (5.3 mi) 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, and Forrestfield station was planned to be above ground. 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.^[20] 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.^[21][22]

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 6.2 metres (20 ft) and have an average depth of 15 metres (49 ft) below ground level. The maximum depth is 26 metres (85 ft) 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 Mandurah line under the Perth central business district in the mid-2000s. The Forrestfield–Airport Link was planned to begin construction in 2016 and open in 2020.^[20]

In late 2014, the project was referred to the Environmental Protection Authority of Western Australia (EPA) and the federal Department of Agriculture, Water and the Environment for environmental approval.^[24] As part of the project is on Perth Airport land, federal environmental approval was sought. The EPA approved the project in July 2015,^[25][26][27] and the Department of Agriculture, Water and the Environment determined that the project did not require assessment and approval from the federal government.^[28]

Expressions of interest to build the Forrestfield–Airport Link opened on 29 January and closed on 12 March 2015.^[29] Five expressions of interest were received, from the following consortia:

• Connecting Forrestfield (Lendlease and Ghella)
• CRCC-BGC-VDM Joint Venture (China Railway Construction Corporation, BGC and VDM)
• Forrestfield Connect (Acciona, BAM and Ferrovial Agroman)
• JHL Joint Venture (Leighton Contractors and John Holland)
• SI-NRW Joint Venture (Salini Impregilo and NRW)^[30]

JHL Joint Venture, SI-NRW Joint Venture, and Forrestfield Connect were shortlisted in April 2015.^[31][32] These consortia entered the request for proposal process in June 2015. Each consortia had to provide a detail and fully costed design by November 2015, which the PTA would then select.^[33][34] Enabling legislation for the Forrestfield–Airport Link was introduced to the Parliament of Western Australia in April 2015^[35] and was passed in October 2015.^[36][37]

SI-NRW Joint Venture was selected as the preferred proponent in February 2016,^[38][39] and in April 2016, the contract was signed at a cost of $1.176 billion. Salini Impregilo held an 80 percent stake in the joint venture and NRW held a 20 percent stake. The contract covered the construction of the Forrestfield–Airport Link and maintenance for ten years.^[40][41] $490 million was funded by the federal government.^[41] 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.^[42] Weston Williamson and GHD Woodhead were appointed by SI-NRW as the designers of the three stations.^[43][44] Other contracts included a $31 million contract with Georgiou Group to build an elevated walkway between Airport Central station and the airport terminal, awarded in late 2018,^[45][46] and a contract extension with Downer EDI–Bombardier Transportation for the construction and maintenance of ten Transperth B-series trains.^[47][48] The total approved budget was $1.861 billion.^[49]

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.^[50][51]

Site establishment at Forrestfield station began in September 2016, with the aim of getting the TBMs launched as soon as possible.^[52] 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.^[53][54][55]

The Labor Party won the 2017 state election, and so the Forrestfield–Airport Link was added to the Metronet program.^[56][57] Within weeks of taking office, Transport Minister Rita Saffioti said that there was a high risk the project would be delayed beyond 2020, accusing the former Liberal government of mismanaging the project. By that point, almost all the planned time contingencies had been used up.^[58] In October 2018, Saffioti said that the former government had refused to give her the Forrestfield–Airport Link's project definition plan, which would have laid out the project's potential risks. She also criticised the former government for not including a turnback siding at Claremont or significant upgrades to Bayswater station in the project's budget.^[59]

A competition to name the two TBMs was launched in April 2017.^[60] In May 2017, the 45 components of the first TBM arrived on site.^[61][62][63] It had been constructed in China by German company Herrenknecht and was assembled on site in High Wycombe. Each TBM cost approximately $20 million, was 130 metres (430 ft) long and weighed 600 tonnes (590 long tons; 660 short tons).^[64] The winning TBM names were announced in June 2017. The first one was named Grace, after a local primary school student with leukaemia. The second was named Sandy, after the sandgroper, a type of insect and a colloquial demonym for Western Australians. Winners were also announced for a competition to decorate the TBMs with artwork by local primary school students.^[65][66]

Construction for Airport Central station began in May 2017,^[67][68] and Belmont by July 2017.^[69] Excavation at Airport Central station began in July 2017 and at Belmont station in February 2018.^[70] In July 2017, TBM Grace was lifted into the Forrestfield dive structure, and began tunnelling on 30 July.^[71][72] TBM Sandy was lifted into the dive structure by September 2017^[73] and began tunnelling on 24 October.^[74][75] On 12 October 2017, construction on the Bayswater dive structure began. By 11 December, the Midland line had been temporarily relocated north to enable further work on the Bayswater dive structure.^[70]

TBM Grace stopped tunnelling on 14 February 2018 due to a ground disturbance issue.^[76][77][78] TBM Sandy stopped on 28 March so that it would not be tunnelling next to Grace.^[79][80] The West Australian reported that SI-NRW JV only stopped the TBMs after Perth Airport expressed concerns.^[81] The TBMs started tunnelling again on 17 April^[82][83] and 24 April respectively.^[84] TBM Grace arrived at Airport Central station on 8 May 2018,^[85][86] and TBM Sandy arrived on 19 May.^[85][87] After undergoing maintenance, both TBMs left the station in July, tunnelling towards Redcliffe.^[88]

In September 2018, a leak developed during the construction of a cross passage between the two tunnels which caused a sinkhole underneath Dundas Road, about 200 metres (660 ft) north Forrestfield station. Groundwater and silt flowed into one of the tunnels, causing flooding in the tunnel. The two TBMs stopped work until the cross passage was repaired. Dundas Road was also closed.^[89][90][91] The final report on the incident said that the pressure of the groundwater damaged a 26-metre (85 ft) section of tunnel by causing "permanent localised distortion to the tunnel shape and movement of the segments which make up the tunnel lining". As a temporary measure, steel frames were put up to support the tunnel while a permanent fix was designed. The chosen permanent solution was for spheroidal graphite iron rings to be placed inside the damaged tunnel area to brace it.^[92] On 18 December 2018, state Transport Minister Rita Saffioti announced that the opening of the Forrestfield–Airport Link had been delayed by one year to 2021 due to the sinkhole, as well as the TBMs moving slower than expected and an increased rate of safety stoppages.^[93][94][95]

On 18 January 2019, the screw conveyor, which moves excavated soil away from the TBM face, was damaged on TBM Grace, which caused the machine to be shut off. TBM Sandy was shut down as well and hairline cracks were soon found during an inspection of its screw conveyor.^[96][97]

TBM Grace reached Redcliffe station on 9 May 2019.^[98][99] After several weeks for maintenance, the TBM left the station bound for Bayswater on 14 June. TBM Sandy reached the station on 6 July^[100] and left the station in early August 2019.^{[citation needed]} In October 2019, TBM Grace reached the Swan River.^[101]

TBM Grace broke through the Bayswater dive structure in February 2020. The TBM was then dismantled and craned out.^[102][103] TBM Sandy broke through the Bayswater dive structure on 20 April 2020, marking the completion of tunnelling for the Forrestfield–Airport Link.^[104][105]

Tracklaying and the installation of overhead line equipment, communications, and signalling systems began in July 2020. SI-NRW JV contracted out the tracklaying to Martinus Rail.^{[106][107][108]} This was completed in July 2021.^[109][110]

In February and March 2021, two shutdowns of the Midland line took place to connect the Forrestfield–Airport Link to the rest of the rail network. On 7 May 2021, Saffioti announced the project had been further delayed, this time saying the line would open in the first half of 2022, blaming delays in the supply of steel and other materials due to the COVID-19 pandemic.^[111][112]

On the day that TBM Grace was launched, over 100 people from the Construction, Forestry, Mining and Energy Union (CFMEU), Electrical Trades Union, and the Australian Manufacturing Workers Union protested, claiming that not enough local workers were used and that overseas workers were being exploited. CFMEU State Secretary Mick Buchan claimed that working conditions were worse on the Forrestfield–Airport Link than in Qatar.^[113]

In October 2017, a worker at Bayswater junction suffered an electric shock when a crane hit high-voltage power lines.^[114][115] Salini Australia was fined $150,000 for the incident and ordered to pay $3,000 in costs.^[116][117] The crew involved did not usually work at the site they were at, and had not gone through an induction for that site.^[118] In July 2018, a worker was knocked unconscious after being struck in the head by a high pressure air hose at Airport Central station. The hose had disconnected from a pipe running along the tunnel wall.^{[119][120][121]} Salini Australia was fined $200,000 for the incident and ordered to pay $2,847.50 in costs.^[122][123] In November 2018, a carpenter was injured at Airport Central station. The CFMEU called for all work on the project to stop so that an independent safety audit could be done. The union claimed that grouting to waterproof the tunnel was not up to the specifications and that the tunnel could collapse due to this. The union also said that workers on 457 visas were made to work in unsafe conditions.^{[124][125][126]}

In December 2018, a worker's arm was crushed by one of the TBM's hydraulic thrust arms.^[117][127] In May 2019, 500 metres (1,600 ft) of slurry pipes fell down in the tunnel as the brackets holding the pipes failed. The pipes were designed to carry slurry to and from the TBMs to control the pressure at the face of the machines. The incident caused TBM Sandy to stop work for about one week.^[128] A former TBM supervisor who quit working on the project due to safety concerns had predicted the pipes would collapse, writing to Transport Minister Rita Saffioti and Industrial Relations Minister Bill Johnston in October 2018 that the pipe brackets were "dangerously deficient". The CFMEU had also expressed concerns about the brackets, saying they did not meet Australian standards. Workers said that if anyone had been near the pipes at the time they collapsed, they would have been killed.^[129] In July 2019, a worker suffered severe chemical burns after standing in contaminated water for seven hours. The water managed to enter his knee high gumboots, causing chemical burns on his legs and feet.^[130][131] The worker was left unable to drive or work more than a year later.^[132]

In September 2022, the United Professional Firefighters Union expressed concern that the Airport line's opening was being rushed. The union wanted for more firefighters to be familiarised with the tunnels before the line opened.^[133]

In 2017, it was publicised that groundwater and soil underneath Perth Airport was contaminated with perfluoroalkyl and polyfluoroalkyl substances (PFAS), which are toxic chemicals formerly used in firefighting foam.^[134][135] About 900,000 cubic metres (32,000,000 cu ft) of soil dug up during tunnelling was contaminated. This soil was temporarily piled up at an industrial lot in Forrestfield before a permanent solution was decided.^[134] It was estimated that the temporary storage would cost $50 million and permanent disposal would cost $270 million.^[136][137] The state wanted to reuse the contaminated soil on the future third runway project at Perth Airport,^[138] but the federal government rejected that proposal.^[139][140] As of March 2023, some of the contaminated soil has been used on the Great Eastern Highway Bypass upgrade, with the rest to be used on future infrastructure projects.^[141]

In July 2021, SI-NRW JV commenced legal action against GHD Group, alleging it was negligent in failing to prepare an adequate design concept.^[142] In particular, SI-NRW JV alleged that GHD breached the tender design agreement for the twelve cross passages and three stations, causing the joint venture to suffer a $17.5 million loss. GHD refuted by saying that the contract was only for the supply of basic design sketches for costings.^[143][144]

The Airport line was originally planned to terminate at Daglish station, as there was already a turnback siding there.^[20] In 2018, it was announced that the terminus had been moved to Claremont station, five stations west of Daglish. This required an upgrade of Claremont station to modern accessibility standards and the construction of two turnback sidings west of the station.^[145][146] Claremont station was chosen as it is located halfway along the Fremantle line and is the line's third busiest station, after Fremantle and Subiaco.^[147] Perth station does not have the space for trains to turn around and stations beyond Claremont do not have a high enough forecast patronage for the extra services for those stations to be worth purchasing more rolling stock.^[148]

In August 2020, John Holland was awarded a $36 million contract to undertake the construction works at Claremont station.^[149][150] From 5 February to 5 April 2021, Claremont station was closed and the Fremantle line was partially shut down to complete the upgrade of Claremont station and build the two turnback sidings.^[151][152] The Fremantle line reopened to full service on 6 April, but Claremont station remained closed as workers discovered problems with the station's original construction.^[153][154] Claremont station reopened on 1 June 2021.^[155]

The original Forrestfield–Airport Link plan only called for $7 million to be spent on minor upgrades to Bayswater station to bring it into compliance with the Disability Discrimination Act 1992. Local residents called for a more substantial upgrade to the station, and some called for the station to be rebuilt underground using the TBMs from the Forrestfield–Airport Link.^{[156][157][158]} The Labor opposition promised a $40 million upgrade of Bayswater station ahead of the 2017 state election.^[159] Labor later won the election, setting into motion planning for the Bayswater station upgrade.^[160] The scope of the upgrade to Bayswater station was revealed on 8 April 2018. The station was planned to be rebuilt as an elevated station with 150-metre (490 ft) long platforms to handle six-car trains. Rebuilding underground was ruled out due to various factors, including high cost and disruption, low benefit, and constraints created by the already under construction Forrestfield–Airport Link. A turnback siding was also planned west of Bayswater station. The rebuilt station was planned to open in 2020, before the Airport line began operations.^{[161][162][163]} In August 2019, when the Morley–Ellenbrook line was confirmed to branch off the Midland line at Bayswater as well, the scope of the Bayswater station rebuild was expanded to building four platforms.^{[164][165][166]}

On 9 April 2020, the contract for the Bayswater station project was awarded to the Evolve Bayswater Alliance, consisting of Coleman Rail and Decmil. The contract was worth $253 million.^{[167][168][169]} Construction began in January 2021.^[170] On 31 March 2023, the old Bayswater station permanently closed, and a 27-day shutdown of the Airport and Midland lines commenced. During the shutdown, 1.8 kilometres (1.1 mi) of track was rebuilt to connect to the new station, the turnback siding was constructed, and the previous station was demolished. The Airport and Midland lines reopened on 27 April^{[171][172][173]} and the new Bayswater station opened on 8 October 2023.^[174][175]

The second last level crossing on the Airport line route, the Moore Street level crossing between Perth and McIver stations, closed on 1 October 2019.^[176] The last level crossing on the Airport line route, the Caledonian Avenue level crossing in Maylands, closed on 15 April 2022. The level crossing's boom gates were down for almost four hours per day, and due to the increase in frequency when the Airport line opens, it was decided the level crossing had to close. Replacing the level crossing with a bridge or underpass was considered, but those options were eliminated as they would require the demolition of several houses.^[177][178]

The first train entered the tunnel in March 2022 to test the tunnel's ventilation system, using the train to measure its resistance to airflow.^[179] An interview with Saffioti released on 3 April 2022 had the minister reiterate the intention to have the line open by the end of June 2022.^[180] Following the state budget on 12 May 2022, the government changed its position, now saying the line will open some time later in the year,^[181][182] although a specific opening date was not provided.^[183][184] A report by the Auditor General of Western Australia released in June 2022 criticised the government for its lack of transparency for major projects, including the Forrestfield–Airport Link. The project was assessed as being within its approved budget of $1.86 billion though.^[185][186]

Three emergency readiness exercises occurred in July 2022.^{[184][187][188]} The West Australian also reported in July that there were delays due to problems with mobile phone coverage in the tunnels and problems with exhaust fans that are meant to extract smoke in the event of a fire.^[187][189] Driver training began on 8 August 2022. It was expected to take eight weeks to complete.^[190]

On 16 August, the opening date was revealed to be Sunday 9 October 2022.^[191] The Forrestfield–Airport Link achieved practical completion on 30 September.^[192] The line was officially opened on 9 October by Prime Minister Anthony Albanese, Premier Mark McGowan, and Transport Minister Saffioti.^[193][194] To celebrate, a community open day was organised for High Wycombe and Redcliffe stations on the day of the opening, which involved live entertainment and food.^[195] Revamped bus services started operating on Monday 10 October.^[100] The Forrestfield–Airport Link ended up $20 million under budget,^[192][196] and remains the only Metronet project not to go over budget.^[197]

High Wycombe station was designed to allow for a future extension south.^[20]: 17 The Perth and Peel @ 3.5 Million plan states that an extension to link the Airport line to the Thornlie line to form a Circle line should be investigated.^[198][199]

The Airport line branch uses 1,067 mm (3 ft 6 in) narrow gauge track^[199] and has a maximum speed of 130 kilometres per hour (81 mph).^[23] Trains are powered by 25 kV 50 Hz AC overhead line equipment. In the tunnels, where space is limited, a rigid overhead conductor rail is used.^[200] The Airport line branch is powered by a substation near High Wycombe station.^[23][200] The Midland and Fremantle lines are powered by substations near East Perth and City West stations.^[23]

The Airport line uses fixed block signalling. As part of Metronet's High Capacity Signalling Project, the Transperth rail network will be upgraded to moving block signalling using communications-based train control (CBTC).^[201][202] As of 2021, the CBTC system is planned to be implemented on the Airport, Midland and Fremantle lines by June 2027. This will allow for 30 trains per hour on the Claremont to Bayswater section of track and 15 trains per hour on the Airport line branch.^[203]

The Airport line branch's and service's eastern terminus is at High Wycombe station, an above ground station next to the Kwinana freight railway and Forrestfield marshalling yard. The station serves High Wycombe, Forrestfield, Maida Vale, Gooseberry Hill, and Kalamunda.^[20]: 17 From there, the line heads north, entering the tunnel soon after and curving west, passing under the freight railway and marshalling yard, entering Perth Airport land, and passing under the site of a future third runway.^[20]: 7 At the 2.4-kilometre (1.5 mi) mark,^[23]: 100 the line reaches Airport Central station, which is an underground station in the car park for Perth Airport terminals one and two. The line travels further west, bending northwest to travel under the airport's two runways.^[20]: 7 At the 5.1-kilometre (3.2 mi) mark,^[23]: 100 the line reaches Redcliffe station, located in the residential area of Redcliffe, 1 kilometre (1 mi) from Perth Airport terminals three and four. The line travels northwest from there, under the former Brearley Avenue and then Tonkin Highway. The line passes under the Swan River and then surfaces just north of Guildford Road in Bayswater.^[20]: 6 The Airport line enters between the two tracks of the Midland line and rises up to ground level to join the Midland line^[204] at the 8.6-kilometre (5.3 mi) mark.^[23]: 100

Along the Midland line, Airport line services continue, stopping at seven stations along the way to Perth station, which is the centre of the Transperth network. Past Perth station, Airport line services travel along the Fremantle line to Claremont station,^[205] where they terminate at the turnback sidings.^[147]

Transperth system map, with the Airport line highlighted

The Airport line has twenty stations, including Showgrounds station, where trains only stop during events at Claremont Showground.^[206] High Wycombe, Airport Central, and Redcliffe stations are in fare zone two, and all other Airport line stations are in fare zone one.^[205]

All stations on the Airport line branch are fully accessible^[207] and have 150-metre (490 ft) long island platforms, long enough for a six-car train.^{[20]: 15–17} Most stations along the Midland and Fremantle line section have only 100-metre (330 ft) platforms, limiting the length of trains that can use the Airport line. The exceptions are Bayswater, East Perth, Perth, and West Leederville stations. The remaining stations are planned to be lengthened eventually.^[208] Along the Midland and Fremantle line section, there are nine stations which are not fully accessible and seven stations which are fully accessible. Factors limiting accessibility include non-compliant ramps, a lack of tactile paving, large platform gaps, and pedestrian level crossings.^[207]

Since 10 October 2022, Airport line services operate every 12 minutes during peak and every 15 minutes outside peak and on weekends and public holidays. At night, services reduce to every half hour or every hour. A few services in the early morning and at night only run between Perth and High Wycombe, with the rest of the services running the full length of the line.^[206] In 2017, Transport Minister Rita Saffioti said that she would like the Airport line to operate earlier than 5 am to cater for FIFO flights.^[219] However, the operating hours later revealed had the first train depart Perth bound for High Wycombe at 5:12 am on weekdays, 5:45 on Saturdays, and 7:08 am on Sundays and public holidays. These operating hours have been criticised as not meeting early morning FIFO flights,^[220] but the government says that the Airport line meets 80% to 85% of all flights in and out of Perth Airport, and that the line needs to be available for maintenance at night. The 12-minute peak frequency required the Midland and Fremantle lines to reduce their peak frequency from every 10 minutes upon the Airport line's opening.^[221]

The Airport line uses Transperth B-series electric multiple units. These trains first entered service in 2004. The final 10 B-series trains were bought specifically for the Airport line and were delivered by 2019.^[222][223] Each B-series train is three cars long, has a maximum speed of 130 kilometres per hour (81 mph) and has two doors on each side per car.^[224]

Six months after opening, the Airport line had 12,000 passengers per day, below the 20,000 passengers predicted.^[225] In the 2022–23 financial year, ending in June 2023, the Airport line had 2,871,117 boardings, making it the least used Transperth train line. In the 2023–24 financial year, the Airport line had 4,860,015 boardings, beating the Midland and Armadale/Thornlie lines.^[226]

• Railways in Perth
• List of airport rail link systems