When the outer-Perth suburb of Ellenbrook was first master-planned in the early 1990s, the State reserved a rail corridor beside the freeway on the promise that trains would follow the houses within a few years. They did not. For three decades, Ellenbrook grew into one of Perth's largest master-planned communities without the train it was designed around, its residents commuting by car along an increasingly congested Tonkin Highway and Reid Highway while successive governments deferred, re-costed and re-announced the missing line. The train finally arrived on 8 December 2024, when the METRONET Morley-Ellenbrook Line opened to passengers — the newest and most symbolically loaded piece of a rail expansion that has become both the signature achievement and the signature cost blowout of WA Labor's near-decade in office (METRONET, Morley-Ellenbrook Line project page; Public Transport Authority, Ellenbrook Line service commencement, Dec-2024).
Ellenbrook's residents are not unique. Across Perth's north, south-east and south, whole growth corridors — Yanchep, Byford, the suburbs along the old Thornlie spur — have spent years waiting on a rail promise first made in 2017. What began as an approximately $3 billion (approx.) election commitment to build new lines and remove level crossings has grown, budget by budget, into a program whose total cost the State's own Budget Papers put above $10 billion by 2023-24, with several individual lines running tens of per cent over their original contract price. The trains are now largely running. The bill for getting them there is the argument that remains.
What the government built
METRONET is WA Labor's flagship infrastructure program, taken to the March 2017 election by then-Opposition Leader Mark McGowan and funded from the government's first budgets after that win. In its original form it promised roughly 72 kilometres of new passenger rail, 18 new stations, the removal of dangerous level crossings and a significant expansion of Perth's train fleet and signalling, at a headline cost pitched at launch in the order of $3 billion (approx.; METRONET, program overview; WA Government election commitments, 2017). Under Premier Roger Cook, who succeeded McGowan in June 2023, the program has entered its delivery phase: four of its most significant new lines have opened in the past eighteen months alone. The Yanchep Rail Extension opened on 15 July 2024, about a year later than the timetable set after the 2021 State Budget. The Morley-Ellenbrook Line opened on 8 December 2024, six weeks ahead of its most recently revised schedule. The Thornlie-Cockburn Link opened on 8 June 2025, extending the old Thornlie spur through to Cockburn Central. The Byford Rail Extension, an eight-kilometre extension of the Armadale line with a new elevated Armadale station and the removal of eight level crossings, opened on 13 October 2025 (METRONET project pages — Yanchep Rail Extension, Morley-Ellenbrook Line, Thornlie-Cockburn Link, Byford Rail Extension — opening dates as published). The program's first major line, the Forrestfield-Airport Link, had already opened on 9 October 2022, around two years behind its original 2020 target.
The projects are jointly funded, with the Commonwealth contributing a significant share alongside State money; the 2024-25 WA Budget alone allocated $4.8 billion in State funding to METRONET over the forward estimates, matched by $2.9 billion in Commonwealth co-investment already committed to the program (approx.; WA Budget Paper No. 2, 2024-25; Australian Government, Infrastructure Investment Program, WA fact sheet, 2024-25).
The strongest case
A 30-year-old promise finally kept, in the one state that can afford to keep it
Put the government's case at its strongest, and it carries real weight. Perth is one of the only major cities of its size still without a comprehensive rapid-transit rail network reaching every growth corridor, and METRONET is genuinely closing that gap: five major projects have now opened in roughly three years, delivering rail to suburbs like Ellenbrook and Byford that were built with rail reservations decades ago and never used them. Level crossing removals bundled into the program have also cut dangerous at-grade intersections across the network, addressing a road-safety problem with its own, separate cost in lives. On cost, the picture is not uniformly bad: the Forrestfield-Airport Link, the program's first and largest single project, had its budget revised down by $174 million from its original approval by the time the Auditor General reviewed it — the one major METRONET project to end up cheaper rather than dearer than first planned, even as it ran late (WA Auditor-General, 2023 Transparency Report: Major Projects). The Auditor General's own 2025 review of major government IT projects, which examined METRONET's signalling and control-system upgrade among ten reviewed projects statewide, attributed cost growth in significant part to two genuinely external forces: a rail network that grew larger and needed more re-signalling than first scoped, and construction-industry cost inflation that has hit every major infrastructure project in Australia since 2021, not just this one (WA Auditor-General, 2025 Transparency Report – Major IT Projects). Finally, WA is arguably the one state in the federation best placed to absorb this kind of cost growth: an eighth consecutive operating surplus, $3.5 billion in 2025-26, funded substantially by iron ore royalties, has kept the State's net debt the lowest, as a share of the economy, of any state in the country (approx.; WA Budget Paper No. 3, 2025-26). A program this large was never going to be delivered at its 2017 price tag; the fairer test may be whether WA got more rail for its money than a state without that fiscal buffer could have managed.
The evidence: five lines, one pattern
Line by line, the primary record shows cost growth that is not an isolated blowout but a pattern repeated across nearly every major project in the program. The Morley-Ellenbrook Line's principal construction contract was let at roughly $1.123 billion; by 2023 its total project cost had grown to about $1.651 billion, an increase of close to half (approx.; METRONET, Morley-Ellenbrook Line project documentation, as reported). The Thornlie-Cockburn Link was originally budgeted at around $716 million; its final construction cost came in at roughly $1.352 billion, close to double the original figure (approx.; METRONET, Thornlie-Cockburn Link project documentation, as reported). The 2022-23 State Budget alone recorded cost increases of roughly $528 million for the Morley-Ellenbrook Line, $375 million for the Yanchep Rail Extension and $244 million for the Thornlie-Cockburn Link in a single year (approx.; WA Budget Paper No. 2, 2022-23). Taken together with cost growth recorded in earlier and later budgets, the program's total cost rose from its roughly $3 billion (approx.) starting point in 2017 to a figure the WA Government's own 2023-24 Budget Papers put at approximately $10.5 billion (approx.; WA Budget Paper No. 2, 2023-24). Some 2024-2025 media reporting, drawing on subsequent budget updates, has put the figure higher again, in the order of $11 billion to $13 billion (approx.; various WA media reporting on total METRONET program cost, 2024-2025) — a range this masthead cannot independently verify to the dollar against a single primary document, but which is consistent with the direction of every budget update the program has received since 2017: up, never down.
Patronage on the newest lines has, so far, run well below what was promised when the spending was approved. A 2020 Project Definition Plan for the Morley-Ellenbrook Line projected the line would carry around 11,700 weekday boardings on opening, rising to 18,000 by 2031. Seven months after the line opened, the Public Transport Authority reported average weekday boardings of roughly 5,364 to 5,500, under half the original projection (approx.; Public Transport Authority data, as reported, Jul-2025). The PTA's own position is that patronage will grow as the surrounding area develops and travel habits shift, and there is genuine reason to expect some catch-up — new rail lines typically take years to reach forecast ridership as land around stations is developed. But a line partly justified by a specific patronage forecast, running at under half that forecast seven months in, is a legitimate test of whether the original business case was realistic rather than merely optimistic.
The critique: a pattern of underestimation, not a one-off
None of these individual project stories is remarkable in isolation; large rail projects run over budget in most jurisdictions, including in states with far less fiscal capacity than WA's. What is harder to defend is the consistency: on the figures above, every major METRONET line except Forrestfield-Airport Link has grown substantially in cost since it was first approved, several by around 40 to 90 per cent (approx.), and the total program figure has climbed in every successive Budget update since 2017 without ever falling. A program that consistently underestimates its own cost at the point of approval is not experiencing bad luck on several separate occasions; it is running a costing process that is not capturing the real price of the work before Parliament, and the public, are told what it will cost.
The WA Auditor-General's Transparency Report: Major Projects series exists specifically to track this pattern across government, not just METRONET. Its 2022 edition flagged five major state projects, including the Forrestfield-Airport Link, as having "high variations" to cost or time; by the 2023 edition, the same report found several of those five "continued to experience increases" in their 2023-24 cost or time budgets rather than stabilising (WA Auditor-General, 2022 and 2023 Transparency Reports: Major Projects). That is a structural finding — a project once flagged as running hot tends to keep running hot — not a one-off correction. The 2025 Transparency Report on Major IT Projects reached a similar structural conclusion about a different slice of government delivery: reviewing ten major projects, including METRONET's signalling upgrade, it found their combined estimated cost had grown by at least $1.6 billion beyond initial estimates, from $2.6 billion to at least $4.2 billion, and concluded plainly that "projects are costing significantly more and taking longer to complete than initially advised to Government by entities" (WA Auditor-General, 2025 Transparency Report – Major IT Projects). That finding is broader than METRONET alone, but METRONET's own signalling and control systems sit inside it, and the underlying diagnosis — initial advice to government understating real cost — is exactly the pattern the rail program's own budget history shows.
Who owns this: McGowan's promise, Cook's price tag
Fairness requires separating what Roger Cook's government caused from what it inherited. METRONET was Mark McGowan's commitment, taken to the 2017 election and funded in his government's first budgets; the bulk of the program's early cost growth, including the 2022-23 Budget's $528 million, $375 million and $244 million increases on three separate lines, was recorded while McGowan was still Premier. Cook became Premier in June 2023 and, since then, has presided over the program's delivery phase rather than its design: four of the five lines discussed here opened on his watch, and his government's first budget as Premier, the 2023-24 Budget, was the one that formally recorded the roughly $10.5 billion total program figure. That timing matters. Cook did not create METRONET's original underestimate, but his government has had every subsequent Budget cycle, and the Auditor-General's repeated warnings, to demonstrate the costing process had improved; on the pattern of increases recorded through 2023-24 and the media-reported range for 2024-25, that improvement has not yet clearly shown up in the numbers. Voters, for their part, returned Cook's government at the March 2025 State election with an increased majority, with the physical arrival of long-promised trains in outer suburbs plausibly working in the government's favour even as the underlying cost story remained largely unresolved (WA Electoral Commission, 2025 WA State Election results, as reported).
Perth got the trains it was promised in 2017. It has not yet been told, in one place, what they actually cost.
The risk to the future
A costing habit that outlives the current boom
The immediate risk is fiscal. METRONET's growing bill has so far been absorbed inside a State Budget running an eighth consecutive surplus on the back of elevated iron ore royalties; that royalty income is cyclical, not guaranteed, and a government that has built a pattern of approving projects at optimistic cost estimates and then finding the real figure later will be far more exposed the next time commodity prices, and the surpluses funding the gap, turn down. WA's net debt is currently the lowest of any state as a share of its economy, but Budget Papers already project it climbing over the forward estimates as the capital program continues; a rail program that keeps costing more than approved is one of the clearest ways that trajectory accelerates (approx.; WA Budget Paper No. 3, 2025-26).
The second risk is to the next set of projects still on the drawing board. METRONET's remaining stages, including further station precincts and any extension of the program beyond its current scope, will be costed and approved using the same processes that produced the pattern documented here. Unless the Auditor-General's repeated finding — that entities are not giving government accurate initial cost advice — is acted on rather than simply re-published each cycle, the next generation of WA rail and transport projects risks entering Parliament's books at the same kind of number the class of 2017 did: a figure everyone involved in approving it should, on the evidence, expect to be wrong.