Executive Summary

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The Sydney Metro West Tunnel is a landmark infrastructure initiative designed to transform Greater Sydney’s rail network. By increasing line capacity by over 50% and reducing peak-hour journey times by up to 10 minutes between Parramatta and the CBD, the project will unlock critical economic corridors and bolster network resilience. Key interchanges at Parramatta, Sydney Olympic Park and new city stations will deliver seamless transfers, while integrated depot facilities support efficient fleet maintenance. Delivered through a hybrid of Design & Construct (D&C) contracts and alliance partnerships, this model fosters innovation, transparent cost-sharing and collaborative risk management—ensuring on-time delivery, budget adherence and alignment of client, contractor and technical advisor interests.

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Technical Specifications

• Tunnel Alignment & TBMs
  • Two 7 m-diameter EPB machines in mixed-face geology; two hard-rock TBMs in sandstone
  • Launch shafts at Westmead and Silverwater; retrieval shafts in the CBD
• Ground Conditions & Support
  • Western Hawkesbury sandstone suited to precast segmental lining
  • Eastern interbedded shale requiring pre-excavation jet grouting and forepoling
  • Composite waterproof membranes integrated behind ring segments
• Lining & Finishes
  • Bolted, gasketed concrete rings for primary support; sprayed concrete in transition zones
  • Integrated longitudinal drainage to manage groundwater ingress
• Rail Systems Integration
  • Slab-track on resilient pads to minimise maintenance and vibration
  • Communications-based train control (CBTC) with dual-fibre backbone
  • Traction power substations at 8 km intervals with UPS backup for emergency running

Governance & Delivery Framework

• Contracting Strategy & Incentives
  • Combination of fixed-price D&C packages for civil works and alliance-style partnerships for systems and fit-out
  • Risk-reward mechanisms encouraging value engineering, innovation and early issue resolution
• Roles & Responsibilities
  • Client (Transport for NSW): overall scope, approvals and funding
  • Principal Engineering Consultant: technical oversight, quality assurance and third-party assurance
  • Contractors: detailed design, construction, testing and handover
  • Alliance Board: joint steering committee with equal client/contractor representation to govern scope changes and cost adjustments
• Decision-Making & Assurance
  • Regular Technical Review Boards to validate design integrity, safety cases and environmental compliance
  • Gateway reviews at key deliverables (e.g., TBM readiness, station box completion, systems integration sign-off)
  • Transparent reporting via a shared project information system, enabling real-time KPI tracking and stakeholder visibility
• Innovation & Continuous Improvement
  • BIM Level 3 federated model for clash detection and buildability workshops
  • Digital twin for asset performance monitoring post-handover
  • Lessons-learned workshops after each tunnelling drive to refine methodologies