Project Overview

TAG Advisory has been engaged by WSP on behalf of the Public Transport Authority of Western Australia (PTA) to provide Class 5 Cost Estimates for 12 new passenger rail alignment options as part of strategic network planning for Perth's future rail expansion. This ongoing comprehensive engagement will deliver high-level order of magnitude cost estimates in early 2026 to inform Multi-Criteria Assessment (MCA) processes and support strategic decision-making for long-term rail network development. The project demands sophisticated understanding of rail infrastructure costs across varied alignment types including at-grade, elevated and underground configurations.

Key Challenges

The scale and complexity of assessing 12 distinct corridor options presents unique challenges in maintaining consistency whilst recognising corridor-specific characteristics. Each alignment option requires consideration of different infrastructure types, geological conditions, urban interfaces and operational integration requirements that significantly impact cost outcomes.

Developing meaningful cost estimates at early planning stages, before detailed design development, requires establishment of robust benchmarked unit rates that can be reliably applied across diverse corridor conditions. The need to inform executive decision-making early in the planning process demands clear communication of cost implications and key cost drivers for each option.

Integration considerations with existing PTA operations add complexity, including impacts on control centres, legacy systems currently under implementation such as High-Capacity Signalling and Radio Systems Replacement and rolling stock requirements. These system-wide implications require careful assessment beyond direct infrastructure costs.

Methodology and Approach

TAG Advisory is implementing a structured methodology developed through successful delivery of similar multi-option assessments, including the Bunbury Faster Rail project which considered over 40 long-list options. Initial briefing meetings with WSP and PTA have established agreement on options, key assumptions, estimate formats and timing for outputs.

Continuous collaboration between TAG Advisory, WSP and PTA is refining alignment options and determining the appropriate level of engineering input required for robust Class 5 Cost Estimates. This ongoing engagement ensures that when PTA's in-house rail engineering team provides engineering drawings in early 2026, TAG Advisory will be fully prepared to deliver comprehensive cost estimates aligned with project requirements.

Development of a comprehensive "shopping list" of infrastructure unit costs will precede individual corridor estimates. These benchmarked rates will be shared with PTA for formal review and acceptance, empowering informed early decisions about corridor options in a controlled manner. Unit rates will differentiate between at-grade, elevated and underground infrastructure based on current construction costs.

The approach includes:

• Application of agreed unit rates to corridor-specific scope and quantities
• Assessment of escalation, procurement models and PTA client costs
• Attendance at MCA workshops to provide high-level cost advice informing route corridor outcomes
• Consideration of construction complexity impacts on costs
• Development of draft cost estimate reports for each of the 12 corridor options
• Ongoing collaboration to refine alignment options and engineering requirements
• Separate consideration of land acquisition, rolling stock and service replacement requirements

Collaborative review processes with WSP will ensure alignment with design outcomes before PTA submission.

Outcomes and Value

TAG Advisory will deliver comprehensive Class 5 Cost Estimates for all 12 corridor options in early 2026, providing PTA with robust financial parameters for strategic network planning. The consistent methodology will enable meaningful comparison between options whilst recognising unique corridor characteristics. Early agreement on benchmarked unit rates is creating transparency and confidence in estimate foundations.

The ongoing collaborative approach between TAG Advisory, WSP and PTA ensures that cost estimates will be based on appropriate engineering detail when drawings are provided. Strategic cost advice during MCA processes will ensure financial viability considerations are appropriately weighted in corridor selection. The structured approach to system integration costs will provide comprehensive understanding of whole-of-network implications.

Conclusion

The Passenger Rail Transport Planning engagement demonstrates TAG Advisory's capability to deliver strategic cost advisory services for complex multi-option rail planning studies. Through ongoing collaboration with WSP and PTA in refining alignment options and engineering requirements, TAG Advisory is positioned to deliver comprehensive cost estimates in early 2026 that will support Perth's long-term public transport network development with confidence in financial parameters.