The Suburban Rail Loop is being delivered in stages. SRL East — 26km of new rail between Cheltenham and Box Hill, with six stations — began construction in 2022 and is planned to open in 2035. SRL North, a future 34km stage with seven stations, has not yet started construction.
The government's own upper estimate for SRL East sits at $34.5 billion. But a Victorian Auditor-General report published in September 2026 found the project is likely to exceed $36 billion, with additional unfunded costs identified that may exceed $2.5 billion on top of that.
The Auditor-General's analysis points to contamination, higher-than-forecast market pricing, and a government decision to slow spending in order to manage state debt as the main causes behind the cost movement.
What this means for planners
Contamination risk at scale
Like the West Gate Tunnel, SRL East carries contamination risk in its tunnelling and station excavation packages. On a project of this scale, even a modest per-cubic-metre contingency for contaminated spoil disposal compounds into a very large number — and it's exactly the kind of risk that's easy to under-provision for at the estimate stage, before ground conditions are fully known.
Government spending decisions as a programme risk
Planners don't usually model "the government decided to slow the rate of spending" as a schedule risk, but on a state-funded mega-project it is one of the largest risks in the register. A funding pace decision, driven by state debt management rather than anything about the project itself, can extend a programme by years without a single construction-related cause changing.
What 2035 means for the workforce pipeline
SRL East alone runs construction from 2022 to a planned 2035 opening — over a decade of sustained demand for tunnelling, systems and civil trades in Melbourne, overlapping with the tail end of Metro Tunnel and West Gate Tunnel delivery. Planners resourcing any concurrent project in this window are competing for the same specialist labour pool.