John Holland Rail (JHR) were responsible for upgrades to the existing MAIN line through the heritage listed Bathurst Station as part of the Fixing Country Rail Round 1 program. The project included installation of Medium Density (MD) sleepers and 60 kg rail through the existing Platform and steel sleepers with 53 kg rail through Bathurst UP sidings 1, 2 & 3 as part of the Country Regional Network (CRN).
The introduction of MD sleepers had a large potential impact on formation thickness such that the geotechnical design required adoption of an alternative (non-standard) JHR CRN approach to reduce the extent of earthworks and possible impact on the existing heritage listed Bathurst Station.
The Mainline works were carried out under weekend possession and included track re-construction through the heritage listed Bathurst Station. Careful control of initial box-out was required to reduce the potential for undermining of the brick platform and possible damage to an underpass structure. Given the site restrictions, close supervision and ongoing design review was necessary to achieve a balance of satisfactory construction/long-term performance outcomes versus potential impact to the existing platform.
D&N was engaged to perform the initial geotechnical investigation works, and provision of detailed design inputs, with a strong focus on track formation optimisation works to reduce excavation works and meet the required shutdown restrictions. We were subsequently retained to provide platform dilapidation survey (pre and post construction), design and implementation of a construction vibration monitoring plan, and construction stage supervision of the earthworks, which required 3 days of rolling 12-hour shifts under strict covid restrictions.
D&N were able to provide an alternative track formation design which met CRN requirements with respect to limiting bulk earthworks (and potential risks to the heritage platform brock arch structure) and designed and implemented a construction monitoring plan to satisfy the project principal (Transport NSW) allowing for the works to be completed without incident and to struct time constraints.
The project required development of on the spot temporary and permanent design solution to changing site constraints during restricted possession works. D&N worked with the design construction team to achieve best for project outcomes.