Major construction has been completed on the New Intercity Fleet Maintenance Facility on the New South Wales (NSW) Central Coast in Australia, in preparation for beginning operations in the coming months.

The project will provide service and maintenance support for the newest generation of rolling-stock to enter service on NSW’s rail network.

This SMEC-designed, state-of-the-art facility was delivered by the John Holland Group (JHG), who engaged SMEC to provide engineering design services for the civil works, combined serviced routes (CSR), utilities, buildings and structures, bridges and piling design. SMEC also provided verification of the new access bridge and roadworks for enabling work, geotechnical investigations and reporting.

“An innovative design was required to enable the construction of heavy-duty foundations to support the train maintenance building and bridge abutments needed for heavy vehicle and rail access. This was a challenge for the team to design a suitable solution in challenging ground conditions, including deep, soft compressible soils,” said SMEC’s Principal Project Manager, Sav Dell’Aquila.

To minimise any impact on the local community from noise caused by traditional pile foundations, a slab-on-ground solution was developed which utilised coal bottom ash, a by-product of power generation.

“The use of light-weight coal bottom ash fill will help to reduce settlement of the slab over time. Combined with extensive construction phase instrumentation and monitoring, this allowed for a slab foundation to be used in the main facility and eliminated the need for a less efficient, and noisy, piled slab,” said Chris Westacott, Senior Associate Engineer – Geotechnics and Tunnels, SMEC.

In Australia, it is estimated that 12.3 million tonnes of coal combustion products (CCPs), including bottom ash, are generated annually.1 The use of coal bottom ash was a practical solution for this project, but also has significant environmental benefits, including re-using a local waste product and reducing transportation cost.

Minor finishing work will continue over the coming months, ahead of the first train entering the site later this year. The new fleet will be introduced progressively starting with the Central Coast and Newcastle Line, followed by the Blue Mountains Line and the South Coast Line.

1 National Waste Report 2018