THE PROBLEM WITH AN INDISPENSABLE NETWORK.

There is a category of infrastructure so essential, so singular in geography and function, that the ordinary disciplines of the market cannot govern it. Roads can be duplicated. Ports have competitors. Even airports, in a large enough country, face rivalry from other gateways. But a coal rail network threading through the specific topography of Queensland’s Bowen Basin — linking specific mines to specific ports across hundreds of kilometres of narrow-gauge track — is something different. It exists once, or not at all. The economics of building a second such network alongside it are not merely difficult; they are, for practical purposes, impossible.

This is the condition that regulators call a natural monopoly, and it is precisely the condition that defines Aurizon’s Central Queensland Coal Network. As there are no substitutes to the central Queensland coal network, the natural monopoly test is satisfied. That single sentence, drawn from regulatory analysis of Queensland infrastructure, carries enormous consequences. If a firm holds the only viable pathway between a mining region and its export ports, and if that firm also operates trains on that pathway, then the potential for market distortion is not theoretical — it is structural, built into the geography itself. The question becomes not whether to regulate, but how.

Queensland’s answer to that question has been, over more than a decade, a sophisticated and contested apparatus of access regulation administered primarily by the Queensland Competition Authority. That apparatus — centred on a formal document called an Access Undertaking — governs who may use the network, on what terms, and at what price. Understanding it is not merely a matter of industry policy. It goes to the heart of how Queensland has chosen to manage the relationship between private infrastructure ownership and public economic interest, and how that relationship is likely to evolve as the coal economy enters an uncertain transition.

Aurizon Network is a wholly owned subsidiary of Aurizon Holdings Limited, which was privatised in November 2010 and manages Australia’s largest coal export rail network, the central Queensland coal network (CQCN). The onchain civic record for this institution is anchored at aurizon.queensland, the permanent namespace through which Queensland’s identity layer registers the entities that shape its economic geography.

THE ARCHITECTURE OF THE CQCN.

Before the regulatory framework can be understood, the physical network must be. Aurizon operates and manages Australia’s largest export coal rail network, the Central Queensland Coal Network. This 2,670 kilometre multi-user track network comprises four major coal systems and one connecting system, serving Queensland’s Bowen Basin coal region: Newlands, Goonyella, Blackwater and Moura, with the Goonyella Abbot Point system as the connecting link. Connecting more than 50 mines to five major export terminals, plus many domestic consumers, the CQCN is a pivotal component to Queensland’s coal industry.

Aurizon’s CQCN operations are governed by 99-year lease arrangements with the State of Queensland. That lease, which dates from the 2010 privatisation of what was then QR National, transferred operational control of the coal lines from the Queensland Government to private hands, while retaining the infrastructure in state ownership. The arrangement was deliberate: the government sought to unlock private capital and management efficiency for the network while preserving its ultimate public character. The business model in the Queensland coalfields was to be similar to Class I railroads in North America, which are vertically integrated with ownership of the trains used to carry freight and the infrastructure they run upon.

That vertical integration — the same entity owning the track and operating trains upon it — is precisely what creates the regulatory problem. Aurizon’s rail haulage division is itself the largest user of the network it owns. It therefore has, in principle, both the incentive and the structural opportunity to disadvantage competing train operators through the terms on which it grants access to its infrastructure. The regulatory framework exists to prevent that from occurring, and to ensure that the price of access reflects efficient costs rather than monopoly rents.

DECLARATION AND THE QCA'S MANDATE.

The legal foundation for regulating access to the CQCN is the declaration of the network under Part 5 of the Queensland Competition Authority Act 1997. The CQCN is declared for third-party access in accordance with Part 5 of the QCA Act, and Aurizon Network must allow third-party train operators to use its network. Declaration is not a trivial instrument. It is a formal finding by the state that a particular piece of infrastructure meets the legal criteria for compulsory access regulation — principally that it constitutes a natural monopoly whose duplication would be economically inefficient.

The Queensland Competition Authority is an independent statutory authority that promotes competition as the basis for enhancing efficiency and growth in the Queensland economy. It was established by the Government of Queensland in 1997. The QCA’s primary role is to ensure monopoly businesses operating in Queensland, particularly in the provision of key infrastructure, do not abuse their market power through unfair pricing or restrictive access arrangements.

In practical terms, the QCA’s role with respect to the CQCN is to oversee the Access Undertaking that Aurizon Network is required to submit, approve, and operate under. Aurizon Network’s access undertaking establishes the framework for access to the coal rail infrastructure in central Queensland. Anyone who wants to apply for access to that rail network must follow the process in the access undertaking. The undertaking is a detailed document specifying reference tariffs — the maximum access charges that Aurizon Network can levy on parties seeking to use the infrastructure — as well as the procedural mechanisms for negotiating access agreements, resolving disputes, and adjusting revenue over time.

In the Queensland rail sector, the QCA ensures that track owned by Aurizon Holdings can also be used by other transport operators, providing customers like coal miners with options for the haulage of their product. This regulation enables competitors to access infrastructure that cannot be economically duplicated, thereby enhancing competition in related markets including rail transport.

THE WACC WARS: A DECADE OF CONTESTED PRICING.

The theory of access regulation is elegant. The practice has been, at times, considerably more contentious. No episode better illustrates the tensions inherent in the system than the extended dispute over UT5 — the fifth generation Access Undertaking — which consumed years of regulatory proceedings, produced a significant write-down for Aurizon, and ultimately required a negotiated settlement between the company and its mining customers.

The process began when on 30 November 2016, Aurizon Network submitted a draft access undertaking for the regulatory period commencing 1 July 2017. At the core of the dispute was the Weighted Average Cost of Capital — the WACC — which determines the rate of return that Aurizon Network is permitted to earn on its regulated asset base. The WACC is not a technical footnote. It is the central mechanism through which the regulator determines whether Aurizon is earning a fair return on its infrastructure, or extracting monopoly rents from its captive network users.

The QCA’s draft decision proposed a WACC of 5.41%, compared with Aurizon Network’s proposed 6.78%. The gap between those figures — more than 130 basis points — represented hundreds of millions of dollars in allowable revenue over the undertaking period. Aurizon was in dispute with the QCA since mid-2017 over the cap on access fees sought by the regulatory body. In February 2018, Aurizon revised its maintenance and operating practices for the CQCN in response to the reduced revenue resulting from the QCA’s draft decision on UT5.

That revision — reducing maintenance expenditure in response to regulatory pressure — became itself a contested point. Critics argued that deferring maintenance on critical freight infrastructure to protect financial returns was precisely the kind of behaviour that access regulation was designed to prevent, by ensuring that the price paid for access reflected genuine efficient costs rather than inflated return expectations. Aurizon Network delivered $400 million to the group’s EBIT but suffered from a regulatory true-up to account for the QCA’s UT5 access undertaking for the Central Queensland Coal Network. Since that finding, Aurizon came to terms with its mining customers on a deal it described as fairer for all parties.

The resolution came through an unusual mechanism: direct negotiation between Aurizon and its major mining customers, producing an agreed outcome that was then submitted to the QCA for approval. Agreements were signed with customers representing more than 90% of volumes on the CQCN, including Anglo American, BHP, Glencore, Idemitsu, Peabody, QCoal and Yancoal. Key points in the proposed amended undertaking included extending the term of the access undertaking to 10 years, from July 1 2017 to June 30 2027, with a Weighted Average Cost of Capital of 5.9% increasing to 6.3% on completion of specified milestones.

The Queensland Competition Authority approved Aurizon Network’s 2017 Access Undertaking (UT5) on 19 December 2019. That approval — three years after the initial submission — marked the end of one of the most technically complex regulatory proceedings in Queensland’s recent economic history. But it was hardly the end of the process. The QCA monitors Aurizon Network’s ongoing compliance with its 2017 access undertaking. Aurizon Network is obliged to undertake a number of activities in accordance with its undertaking, some of which require QCA approval, including annual approval of capital expenditure, revenue cap adjustments and reference tariff variations.

THE REVENUE CAP, THE TARIFF, AND THE RISK ALLOCATION.

Understanding what an access undertaking actually does in practice requires grasping a somewhat counterintuitive feature of how regulated monopoly revenue works. Aurizon Network does not simply charge a fixed price per tonne. It operates under what regulators call a revenue cap regime, and the implications of that structure are significant for every mine operator in the Bowen Basin.

Aurizon Network operates under a revenue cap regime, where any over- or under-recovery of its approved revenues in any given year is returned or recouped through a reference tariff adjustment two years later. The adjustment is referred to as a revenue adjustment amount. This mechanism creates a feedback loop between actual throughput and the tariffs charged in future periods. When coal volumes fall — whether due to market conditions, weather events, or industrial disruption — Aurizon Network under-recovers relative to its approved revenue allowance. Those under-recovered amounts are then recouped through higher tariffs in subsequent years.

Tariffs adjust for changes in volumes to ensure the CQCN earns a fair return, meaning tariffs would increase to offset lower volumes in an industry downturn. This structure makes earnings defensive, but only to a point. Should conditions deteriorate and major mines start closing, tariffs for remaining mines increase to offset the fall in volumes transported over the rail network, pushing the remaining mines up the cost curve and making them less economically viable.

This dynamic — where the regulated network’s revenue stability comes partly at the expense of the mine operators’ cost predictability — is one of the subtler tensions in the Queensland coal chain. It means that the access regime, while preventing monopoly extraction in the short term, creates its own form of structural risk: a ratcheting tariff effect that can accelerate economic stress among mining operators during downturns. This is not a failure of regulatory design so much as an inherent feature of the regulated natural monopoly model, and it is one reason why the exact calibration of the WACC and allowed revenues matters so much to every participant in the supply chain.

Despite being highly regulated and needing large capital investment, the CQCN is a monopolistic rail system that provides Aurizon with highly predictable long-term revenue. Typically, regulated tariffs are the main source of Aurizon’s revenue from the CQCN, with the access undertaking set every three to five years.

"The QCA uses pricing and other regulatory arrangements, based on sound economic and commercial principles, to encourage monopoly businesses to operate responsibly in the absence of normal competitive market forces."

That statement, drawn from the QCA’s own description of its mandate, captures the philosophical ambition of the regime: not to simulate competition where none exists, but to use regulatory instruments to achieve outcomes that competition would produce if it could. The question of whether those instruments are well-calibrated — whether the allowed return is fair to both the infrastructure owner and its users — is one that has generated, and will continue to generate, sustained technical and legal debate.

THE ACCC, ONE RAIL, AND THE LIMITS OF ABOVE-RAIL COMPETITION.

The regulation of the CQCN does not occur in isolation. The below-rail monopoly that Aurizon Network holds over the physical infrastructure coexists with a market for above-rail services — the locomotives and wagons that actually move coal — where some degree of competition is theoretically possible. The integrity of the access regime depends, in part, on ensuring that Aurizon’s combined role as infrastructure owner and above-rail operator does not foreclose that competition.

This tension became acute in 2021 when Aurizon sought to acquire One Rail Australia, a competing rail operator. In October 2021, Aurizon agreed terms to purchase One Rail Australia. The transaction was approved in July 2022 by the Australian Competition and Consumer Commission after the commission accepted Aurizon’s court-enforceable undertaking to dispose of the seller’s Hunter Valley coal haulage and Queensland coal haulage business to maintain competition levels.

The ACCC’s insistence on divestiture before approving the acquisition reflected a judgment that allowing Aurizon to absorb a competitor’s coal haulage operations in both Queensland and New South Wales would substantially lessen competition in above-rail markets. The transaction proceeded only after Aurizon agreed to divest One Rail’s Queensland and Hunter Valley coal businesses, preserving the possibility of competition at the train-operations level even where competition at the infrastructure level is impossible.

That distinction — between competition in above-rail services and the inevitable monopoly of below-rail infrastructure — is the structural feature around which the entire regulatory architecture of the CQCN is built. Aurizon’s rail haulage division is the largest user of the CQCN, but it must allow other above-rail operators access, in accordance with access undertakings approved by the Queensland Competition Authority. The functional separation between Aurizon Network as infrastructure manager and Aurizon Operations as train operator is meant to ensure that the below-rail business cannot use its regulatory position to advantage the above-rail business at the expense of competitors.

UT5+: NEGOTIATING THE NEXT DECADE.

As the current undertaking approaches its scheduled expiry on 30 June 2027, the regulatory process has entered a new phase. In December 2025, Aurizon Network lodged what it called UT5+ — a proposed draft amending access undertaking that would extend the current framework for a further decade. On 22 December 2025, the QCA received a draft amending access undertaking from Aurizon Network seeking to amend the 2017 access undertaking and extend the expiry of the undertaking until 30 June 2037. The QCA commenced an investigation to decide whether to approve or refuse Aurizon Network’s 2025 UT5 DAAU.

The proposed undertaking introduces a performance-linked Throughput Payment, incentivising efficient network operations, new five-year rolling access agreements to improve customer rail capacity planning, and a revenue uplift for Aurizon Network relative to the existing UT5 methodology, with updated WACC parameters. The UT5+ access undertaking was lodged with support from customers representing 68% of contracted CQCN tonnages — a negotiated consensus that, while not unanimous, reflects substantially broader industry alignment than had existed during the contentious UT5 process.

For Aurizon, the agreement is expected to deliver a revenue uplift via changes to depreciation and the introduction of a new Throughput Payment, which partially replaces the existing WACC uplift. The updated methodology will also bring forward future cash flows and reflect a more accurate cost of debt within WACC calculations. UT5+ remains subject to QCA approval, so the final terms could still change after regulatory review.

The introduction of a performance-linked payment component is noteworthy. Earlier iterations of the access regime were criticised, from the mines’ perspective, for giving Aurizon Network insufficient incentive to maintain and improve network performance, since its revenue was largely protected by the cap regime regardless of throughput outcomes. A throughput-linked payment mechanism attempts to align Aurizon’s financial interest more closely with the supply chain performance that mine operators depend on. Whether that alignment is sufficiently strong, and whether the QCA will ultimately approve the specific parameters proposed, remains to be determined through the regulatory process.

The shadow cast over this negotiation — and over every future regulatory cycle — is the energy transition. The long-term viability of the metallurgical coal market that underpins most CQCN throughput is contested. A ten-year access undertaking running to 2037 must accommodate a range of scenarios from continuing strong demand to significant volume decline, with the tariff structure’s inherent ratchet mechanism creating meaningful downside risk for the mines that remain should others close. How the QCA approaches this uncertainty in its assessment of the proposed UT5+ will be a significant test of regulatory prudence.

WHAT REGULATION REVEALS ABOUT INFRASTRUCTURE AND IDENTITY.

There is something revealing about how a society chooses to regulate its essential infrastructure. The decades-long arc of QCA oversight over the CQCN — from the initial framing of the declaration regime, through successive access undertakings, through the contested WACC proceedings of the UT5 period, and into the emerging UT5+ framework — is not merely a story about tariff methodology. It is a story about the terms on which public benefit is extracted from private ownership of infrastructure that the public cannot afford to lose.

Queensland chose, in 2010, to privatise the management of its coal rail network while retaining its ultimate ownership through the state. That choice imposed an obligation: if private management was to be permitted, the public interest in efficient and open access had to be preserved through other means. The QCA’s oversight of the Access Undertaking is those other means — the institutional machinery through which the state enforces its residual claim on infrastructure that was built, in significant part, by public investment and public decision over many decades.

The stakes of that machinery are not abstract. Every basis point in the WACC represents real cost flowing through the supply chain to mine operators, to the workers and communities that depend on those mines, and to the Queensland economy that depends on export coal royalties and employment. The regulatory framework is, in this sense, a civic document as much as an economic one — an expression of what Queensland has decided about the balance between investor returns and user costs for infrastructure that no market can replace.

The CQCN is an open-access regulated monopoly, which cannot be replicated. While this is an impenetrable barrier to entry, pricing is set by the regulator, negating most monopoly benefits. That formulation, precise in its economic framing, contains within it the entire project of access regulation: to hold the line, through institutional design and annual oversight, between a legitimate return on infrastructure investment and an extraction that the natural monopoly position would otherwise permit.

As Queensland’s identity layer builds its permanent onchain record of the institutions and systems that define the state’s economic character, the regulatory architecture of the CQCN stands as one of the more consequential and underappreciated entries. The decisions made in QCA offices about WACC parameters and revenue caps reverberate through the Bowen Basin, through the port terminals at Gladstone and Hay Point, through the regional communities whose employment depends on the economics of the coal chain, and through the state’s fiscal position. aurizon.queensland names not merely a company but a regulatory relationship — the ongoing negotiation between private ownership and public obligation that defines what it means to hold a natural monopoly under lease from the people of Queensland.