Rawlinsons (W.A.) was recently engaged by the Public Transport Authority from 2018 to early 2021, providing cost estimation services on Stage 2 Metronet projects including: Morley Ellenbrook Line, Karnup Station, Midland Station and line extension, Byford Rail Extension, Metronet Level Crossing Removal Oats Street (Carlisle) and Metronet Level Crossing Removal Wharf Street (Cannington).
These rail infrastructure projects follow in our company history of providing estimating services on both the Perth to Joondalup Railway line along with the Perth to Mandurah Railway line. They are all large scale, multi-disciplinary, complex infrastructure projects that go a long way to shaping the future of Perth and how we move, work and live within our city.
Rawlinson’s (W.A) role was to provide full cost estimating services that provided each project with a total escalated outturn cost at both P50 and P90 confidence levels. All cost estimates were undertaken in accordance with the Department of Infrastructure and Redevelopment (DIRD) Guidelines which is a required for projects seeking funding from Infrastructure Australia. Additionally, Rawlinsons (W.A) provided advice on procurement and contractual relationships for the proposed projects.
As part of our scope of work we were required to provide probabilistic project contingency to calculate P50 and P90contingency values. We collaborated with the project teams to establish a robust project risk register and assign high and low values to each item. Contingent and inherent risks were both calculated. The cost data for both inherent and contingent risks are entered into the @Risk software which runs a Monte Carlo Simulation for 10,000 iterations using appropriate distributions. Based on this we were able to calculate P50 and P90 probability confidence.
To complete the capital cost estimates we provided cash flow forecasts and in turn produced an escalated cash flow which gave us the Total Escalated Outturn Cost for the project. Each estimate is accompanied by a detailed report outing estimate methodology, constructability issues, key assumptions and exclusions, productivity analysis and risk profile.
A large proportion of the cost estimation involved the diversion, relocation or replacement of major utility infrastructure services including Western Power. Rawlinsons worked with the engineers and utilised utility providers scope requirements to establish early budgets that would capture the initial known scope of works as well as allow efficient contingency to cover the largely undefined works and associated risks.
One of the key roles Rawlinsons performed on the various projects was value engineering. A lot of the initial designs provided by the design teams were well in excess of project funding. Rawlinson worked with both the client and project engineers to refine designs, limited scope creep and provide more cost effective engineering solutions to achieve the same outcomes. This resulted in a substantial capital cost reduction on the Byford Rail Extension Project.
At the time of this summary, all projects are currently moving to the delivery phase of the works and are on budget.