The Mandurah line is a suburban railway line in Western Australia that links Perth's central business district (CBD) with Mandurah to the south. Operated by the state's Public Transport Authority (PTA) as part of the Transperth system, the Mandurah line is long and has thirteen stations. The line operates as a through service with the Yanchep line to the north, and includes two stations in the William Street tunnel under the CBD. It continues south via the Kwinana Freeway's median strip, where five of its stations are located, then diverges from the freeway for the southernmost six stations in the cities of Kwinana, Rockingham and Mandurah.
Known during planning and construction as the Southern Suburbs Railway or the South West Metropolitan Railway, early planning for the line began in 1989 during planning for the Yanchep line. In 1994, a route branching off the Armadale line at Kenwick to follow the Kwinana freight railway and Kwinana Freeway was selected, but after the election of a Labor state government in 2001, the planned route was changed to go via a tunnel under the CBD. The Mandurah line, which was built as part of the New MetroRail project, was divided into eight contract packages. It was designed similarly to the Yanchep line, using widely spaced stations with bus interchanges and large park-and-rides.
Construction began in February 2004; it was disrupted by labour strikes and technical issues, particularly on the CBD tunnel section. Originally planned to open between Perth and Warnbro station in 2006 and between Warnbro and Mandurah in 2007, the tunnel opened on 15October 2007 and the rest of the line opened on 23December 2007. The total cost of New MetroRail was A$1.725billion. Two infill stations have since opened: Aubin Grove in April 2017 and Lakelands in June 2023. In June 2025, the Thornlie line was extended to Cockburn Central station on the Mandurah line, completing the Kenwick route that was planned before 2001.
B-series and C-series trains are the main rolling stock used on the Mandurah line, and A-series trains were also formerly common. Trains run at a fifteen-minute headway during most times, reducing to as short as a five-minute headway in peak periods, when some services terminate at Cockburn Central. The travel time from Perth to Mandurah is 54 minutes. Initial patronage has significantly exceeded forecasts. The line recorded 23,728,644 boardings in the year to June 2026, making it the busiest Transperth railway line.
History Route selection In February 1989, ahead of that year's state election, the Government of Western Australia announced it was investigating the construction of a railway line from Perth to Rockingham or Mandurah. At the time, planning was underway for the Northern Suburbs Railway, now known as the Yanchep line. Later that year, the South West Rapid Transit Study was formed; its steering committee consisted of representatives from the Department of Transport, the Main Roads Department, the Department of Planning and Urban Development, Transperth and Westrail. In 1990, the committee released a report outlining two route options: an extension of the Fremantle line or a branch off the Armadale line at Kenwick, both of which made use of freight rail corridors. The premier of Western Australia, Carmen Lawrence, announced in February 1992 the Fremantle option had been chosen. By this stage, bus rapid transit had been ruled out. The South West Area Transit (SWAT) Steering Committee was formed to consider rail-based alternatives, such as light rail. The section between Fremantle and Rockingham was scheduled to open in 1996, with the Rockingham-to-Mandurah section opening five years later. Legislation to build the railway was introduced to the Parliament of Western Australia later that year. By January 1993, the SWAT Steering Committee had recommended to government the rail line should be an extension of the existing network, and not light rail.
Independently of the SWAT Steering Committee, Westrail investigated a direct route from Perth to Mandurah via Thomsons Lake at the behest of the Department of Planning and Urban Development. The Kwinana Freeway's median strip south of the Narrows Bridge was considered too narrow compared to that of the Mitchell Freeway, where the Northern Suburbs Railway was constructed. An underground route from Perth to the Mount Henry Bridge was determined to cost about A$800million, which was considered too expensive.
Following the 1993 state election, the new Liberal government deferred the construction of the railway to Mandurah, but continued its planning. The Kenwick route became the preferred option because its travel time to Perth was shorter than that of the Fremantle route. The Kenwick route was reserved in the Metropolitan Region Scheme in December 1994. Ahead of the 1996 state election, Labor leader Geoff Gallop committed to building within four years a railway line from Fremantle to Rockingham that would be extended to Mandurah if Labor won a second term in government. Western Australia's Transport Minister Eric Charlton instead pledged the new line would branch off the Armadale line at Kenwick.
Kenwick route In August 1997, the Liberal state government commissioned a master plan for the Kenwick route. The cabinet endorsed the South West Metropolitan Railway Master Plan and released it in March 1999. The plan outlined the route of the Mandurah line and its construction. The new track was to be long; including existing track between Perth and Kenwick, the distance from Perth to Mandurah would have been . Commencing at Kenwick, the railway would run parallel to the Kwinana freight railway until the Glen Iris estate in Jandakot, then south along the Kwinana Freeway's median strip to Kwinana, then southwest through Kwinana, Rockingham and Mandurah along the alignment reserved in the Metropolitan Region Scheme. Three options were given for the railway's route through Rockingham. The new line was forecast to cost, in total, $941million, of which $629million was for infrastructure and $312million was for rolling stock. The line was planned to open as far as Thomsons Lake in 2005, with an extension to Rockingham and Mandurah opening in 2006. Two busways were built to supplement the railway; one along the Kwinana Freeway from Perth to the Murdoch Park 'n' Ride, and one from Fremantle to Rockingham.
Stations were planned at Thornlie, Nicholson Road, Canning Vale (later renamed Ranford Road), South Lake, Thomsons Lake (later renamed Cockburn Central), Thomas Road (later renamed Kwinana), Leda (later renamed Wellard), one or two stations in Rockingham, Waikiki (later renamed Warnbro), and Mandurah, with provision for additional intermediate stations in the future. Upgrades along the Armadale line would have been necessary due to short station spacing and level crossings. Lathlain and Welshpool stations were to be closed, and Carlisle and Victoria Park stations were to be rebuilt and relocated, in part to fill the gap left by the closure of Lathlain station. Perth, Oats Street, Queens Park and Beckenham stations were to be upgraded as well. Several road and pedestrian level crossings were to be grade separated. The new service was to operate as a through service with the Yanchep line, known at the time as the Joondalup line, due to the lines' similar levels of patronage, leaving the Armadale line to terminate at Perth station.
The master plan gave three options for the railway's route through Rockingham. Two options would run via Rockingham city centre, the first having a tunnel and the second having a tunnel, each with a station in the city centre and at Ennis Avenue. The third option would run along Rockingham's outskirts, bypassing the city centre, with one station at Dixon Road. The options were costed at $143million, $107million and $31million, respectively. The City of Rockingham was strongly in favour of the first two options, but in the first two options, trains travelling through Rockingham would take another five minutes, and demand modelling projected similar patronage for all three options. Two weeks after the master plan was released, a task force was formed to meet with members of the Rockingham community and receive submissions. Out of nine thousand written submissions, 93 percent supported running the route through the city centre. In October 2000, the state government announced that a route through the Rockingham city centre had been chosen.
Excluding Rockingham, three short tunnels were required for this route, which were constructed ahead of time. The two tunnels for the railway to enter and exit the Kwinana Freeway median strip, at Glen Iris and Anketell, were constructed for $30million as part of a project to upgrade and extend the freeway. The northbound freeway carriageway between Kwinana and Jandakot was also moved west to accommodate the railway line in the median strip. A tunnel was constructed in Kenwick as part of the extension of Roe Highway and the realignment of Albany Highway. Between Warnbro and Mandurah, the line was planned to have a single track, allowing a maximum of two trains per hour to Mandurah. The plan for that section was changed to double track in 2000 for an additional $20million.
State Parliament passed the Railway (Northern and Southern Urban Extensions) Act 1999 in November 1999, authorising the construction of the railway to Mandurah, and the extension of the Joondalup line to Clarkson and Butler. A new master plan with revisions was released in April 2000, and in June 2000, the South West Metropolitan Railway project and the Joondalup line extension to Clarkson were merged into one project, known as the Perth Urban Rail Development Project. In October 2000, the funding arrangements were decided, allowing the planned opening date to be brought forward to 2004 for Kenwick to Thomsons Lake, and 2005 for the full line to Mandurah. The two projects combined were forecast to cost $1.1billion, of which the privatisation of AlintaGas would provide $300million, a railcar lease would provide $398million, and the remaining $449million would be funded by government debt.
Direct route While in opposition, the Labor Party opposed the Kenwick route and wanted the railway to be an extension of the Fremantle line. Murdoch University professor and transport expert Peter Newman criticised the route for not going via Fremantle, but by 1999, had changed to advocating for a direct route along the Kwinana Freeway between Perth and Jandakot. By 2000, the Labor Party was in favour of the Kenwick route; the party did not want to appear too critical, according to the member of parliament (MP) for Rockingham, Mark McGowan. The Department of Transport opposed the direct route, saying it would require the closure of the Kwinana Freeway bus lanes and serve a lower population than the Kenwick route. The following year, Labor was elected to state government, and in July 2001, the new Cabinet approved a change from the Kenwick route to the direct route along the Kwinana Freeway. This direct route involved a tunnel to bring the line through the central business district (CBD). The route's main advantage was that it made for a shorter, more direct journey from Mandurah to Perth, reducing the journey time by twelve minutes. It also allowed for stations near Murdoch University and at the southern side of the Perth CBD, but was more expensive, requiring parts of the original plan to be cut. To make use of the already-constructed Kenwick tunnel, the Thornlie line was to be built as a one-station spur off the Armadale line. The Mandurah line's opening date was postponed for a year, but the government committed to not exceeding the cost of the Kenwick route.