Melbourne’s Metro Tunnel Project has entered a new stage of construction, with crews preparing to lay track through the completed tunnels – a step closer to getting more than half a million extra passengers on the rail network during the peaks every week.
The first of almost 40km of rail has been delivered to the Metro Tunnel’s western entrance in the past week as works gear up to install rail systems and tracks through the project’s twin nine-kilometre tunnels.
Work on the rail tunnel and station fit-outs have been ramping up since four tunnel boring machines finished the nine kilometre long, 6.3 metre high rail tunnels in May 2021, excavating more than 600,000 cubic metres of rock and soil.
At the five new stations – Arden, Parkville, State Library, Town Hall and Anzac – crews are installing features such as escalators and lifts and fitting out back-of-house equipment rooms. The station platforms are taking shape up to 30m underground, along with ceilings, stairs, walls and mechanical and electrical systems.
Inside the tunnels crews are fixing brackets and cable trays to the tunnel walls to hold electrical and communication cabling in place, as well as installing fire safety pipework and signalling equipment.
Specially designed gantries with bespoke “zero gravity” lifting arms travel along the length of the tunnels on wheels, allowing workers to carefully manoeuvre the equipment into place as they go. These machines make working on the project much safer by reducing the need for manual handling.
Across the 18km of tunnel length workers will install almost 50,000 brackets, 15km of elevated steel walkway for emergency and maintenance access, almost 500km of electrical and fibre cables, 16km of pipework to carry fire retardant, and more than 3000 lights.
Installing the track will take up to a year, beginning with crews laying 4000 high-performance precast concrete panels through the twin tunnels. There are 300 different panel shapes to account for the varying curvature and elevation of the tunnels as they wind from Kensington to South Yarra up to 30m underground.
The state-of-the-art concrete panels – similar to track used in other world class metro systems – require significantly less maintenance compared to conventional surface railway tracks, which use sleepers laid on ballast.
From mid-2022 crews will install 165 metre lengths of steel rail, progressively clipping them to the concrete panels and welding them together to form a continuous rail line along the length of the tunnels.
Once overhead power and the new high-tech signalling is installed in the tunnels and stations, along with more than 2km of platform screen doors, testing will begin in the tunnels with Melbourne’s new fleet of bigger, more modern trains in 2023.
When it opens in 2025, the Metro Tunnel will create a new end-to-end line from Cranbourne/Pakenham in the south east to Sunbury in the west.
That will save 40 minutes on a return journey to Parkville for Sunbury Line passengers and 30 minutes for Cranbourne/Pakenham Line passengers and connecting to the future Melbourne Airport Rail line via Sunshine.
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