The new Metro Tunnel will let more trains run in and out of the city by giving the Cranbourne, Pakenham and Sunbury lines their own tunnel through the CBD. Visit melbournemetro.vic.gov.au for more information

Building rail tunnels under busy inner-city Melbourne presents a number of design and construction challenges. However, cities around
the world are building metro systems in densely populated urban areas, demonstrating that these challenges can be overcome with careful planning and smart construction.

TBMs are large machines that tunnel through ground, progressively installing concrete linings to support the excavated tunnel. The excavated material is transported through the machine to the surface for removal by trucks.

TBMs are typically used in the construction of long underground tunnels. They are tailored for specific conditions and can be several metres in diameter, more than 100 metres long and weigh up to 1,000 tonnes.

This video contains footage from the Crossrail Project in London used with permission.