Transport for New South Wales

Web Link

TfNSW are planning the upgrade of the Great Western Highway between Katoomba and Lithgow passing through Blue Mountains townships of Medlow Bath, Blackheath, Mt Victoria and Little Hartley. The project will upgrade the existing alignment that meanders through the mountains to a high speed divided dual carriageway to improve safety and reduced longitudinal grades to improve freight productivity and provide a more reliable journey for thousands of residents, commuters, tourists and freight operators who travel in, around and through the Blue Mountains.

CCHD was engaged by TfNSW between 2018 and 2022 to manage and develop strategic options and preferred reference designs for this 36km long section of the GWH corridor.

The majority of CCHD’s team was involved in this project across the following disciplines:

  • Alignment options and strategic civil design of roadway and tunnels
  • Preliminary feasibility design of major bridge structures
  • Preliminary environmental investigation
  • Rapid economic appraisal
  • Workshop facilitation
  • Community consultation and presentation
  • Project visualisations
  • Cost planning and estimating

RMS Contractor Performance Report Overall 95% (Superior)

Client Quote: CCHD has continued to provide exceptional service that has added great value to the Great Western Highway Duplication project. The team is proactive and are always willing to take on new challenges to achieve project milestones to a high standard. Paul Peters Report Date: 27/08/2020

Project Overview

Katoomba to Medlow Bath

With extremely challenging topography at Pulpit Hill (between Katoomba and Medlow Bath), the CCHD team developed an alignment that achieves the required design criteria (design speed/cross section/etc.) with careful consideration of the associated constructability challenges for traffic management during construction of major road realignment. Working with Focus Bridge Engineers in developing bridge options, CCHD developed an alignment compatible with the major bridge structure proposed.

Medlow Bath to Blackheath

The section of the Great Western Highway between Medlow Bath and Blackheath runs parallel to the Blue Mountains Railway line on the west and National Park on the east. Early in the strategic design phase CCHD developed an alignment that achieves the design criteria, provides for construction staging/traffic switches, included required stormwater basins as calculated by sub-consultant Lyall and Associates, including maintenance access and off-road shared path. This ensure confidence in the projects future footprint and so establish the project boundary and enable the national parks revocation process to begin – a critical item on the project program.

Medlow Bath Town Centre

Working with Focus Bridge Engineers, CCHD initially investigated several locations for alternate crossing points for the road and pedestrian bridges over the existing Blue Mountains Railway line. This involved consideration of bridge structure type, span and construction methodology (over rail), rail clearance envelope and appropriate abutment offsets to retain maintenance access along the rail corridor. Following this optioneering process and assessment of impacts, it was decided an upgrade of the existing corridor was the best solution, however with several heritage constraints in this section of the corridor, CCHD worked with urban planners to develop a “best fit” alignment and cross section that achieves the design criteria and safe functionality while minimising impact on heritage items and achieving urban design outcomes.

Blackheath (to Mt Victoria to Little Hartley)

CCHD developed a multitude of road alignment options both prior to and during the community consultation phase. These included:

  • Upgrade of existing alignment – including intersection upgrades and options to remove rail level crossing via road/pedestrian underpass.
  • Inner Blackheath bypass – Provide new dual carriageway west of the existing Blue Mountains Railway line with alternate crossing points with minimal connections to local road network. Including at-grade, slot and cut and cover vertical alignments.
  • Outer Blackheath Bypass – Alternate alignments around the outer extent of Blackheath township. Encountering extremely challenging topography the alignments included several large (balanced cantilever) bridges.