Tunnel works

Construction of SRL East powering ahead, with preparations well underway for SRL East tunnelling to start in 2026.

Tunnel boring machines (TBMs) are arriving on site in late 2025 to carve 26km of twin tunnels between Cheltenham and Box Hill. At their deepest point, the tunnels will be approximately 60m below ground, the equivalent depth of a 16-storey building.

Work sites

TBMs will launch from Clarinda to excavate the southern section of tunnels between Cheltenham and Glen Waverley, and from Burwood to dig the northern section of tunnels between Glen Waverley and Box Hill.

The 2 SRL East tunnelling contractors are preparing to launch TBMs from these sites from 2026.

Map showing the location of the TBMs for SRL

About Burwood

Four TBMs will launch from Burwood – 2 will tunnel towards Glen Waverley and 2 towards Box Hill.

Excavation of the first TBM launch site is powering ahead in Burwood, in preparation for the start of tunnelling towards Glen Waverley in 2026, with crews digging a 19m deep, 38m long and 29m wide space.

A second launch site will then be built for the TBMs which will head north to Box Hill.

Find out more about Burwood

About Clarinda

Four TBMs will launch from Clarinda – 2 will tunnel west towards Cheltenham via the train stabling facility at Heatherton, and 2 will tunnel north to Glen Waverley via Clayton and Monash.

The 2 TBMs heading towards Cheltenham will come to the surface at the eastern tunnel entrance of the train stabling facility and will be transported to the western tunnel entrance, before relaunching and continuing to tunnel to Cheltenham.

See how the TBMs will launch from the Clarinda site.

Find out more about Clarinda

About the TBMs

The 8 TBMs needed for SRL East have been supplied by 2 of the world’s leading manufacturers of TBMs - Herrenknecht and the China Railway Engineering Equipment Group (CREG).

The 4 Herrenknecht TBMs – which are 7.29m in diameter and 100m to 150m long - will tunnel the southern section between Cheltenham and Glen Waverley.

Two of the Herrenknecht TBMs will travel west to Cheltenham - via the train stabling facility at Heatherton - and the other 2 will head north to Glen Waverley. The southbound TBMs can also be converted for use as earth pressure balance machines, to suit ground conditions along the way.

Herrenknecht TBMs are also being used on the Snowy 2.0 project, as well as the West Gate Tunnel ; North East Link; Sydney Metro; South Road Project in Adelaide, and the Legacy Way, Airport Link and Clem Jones Tunnel in Brisbane.

Two of the Herrenknecht TBMs for SRL East are now under construction in Guangzhou, China, and the other 2 will be rebuilt following their use on the Sydney Metro project, which will significantly reduce the carbon footprint of SRL East. Refurbishment of long gantries for these two machines will be carried out at Herrenknecht’s Newcastle facility in New South Wales.

All four TBMs for the southern section of the tunnels will launch from Clarinda – the first two in 2026.

The 4 CREG TBMs are currently being built in Zhengzhou, China. Two will launch from Burwood next year, tunnelling south to Glen Waverley, with the other 2 heading north towards Box Hill at a later date.

CREG already provides TBMs for 2 other major infrastructure projects in Australia - Snowy 2.0, and the West Harbour Tunnel Project in Sydney.

All 8 SRL TBMs will be powered by 100% renewable electricity.

FAQs

TBMs vary in dimension and are highly specialised pieces of machinery designed to excavate tunnels beneath the surface with customisation to suit underground conditions.

The TBM’s rotating cutterheads carve their way through soil and rock, creating tunnels that are safe, durable, and built to last for generations.

They are also equipped with a state-of-the-art navigation system, and facilities for workers, including an office, kitchen and toilets.

TBMs operate like moving underground factories, using their giant rotating cutting heads to grind and excavate rock and soil. As each TBM moves forward, it installs a concrete lining in its wake - forming the lining of the tunnel.

The SRL East twin tunnels will be constructed deep underground, at an average depth of 26 metres – or the equivalent of 6 storeys underground.

Cities around the world regularly build underground rail systems in densely populated urban areas, including Melbourne’s own Metro Tunnel.

With thousands of tunnels operating around the world and millions of people living above them with no impact on their daily lives, tunnels can be built safely and without affecting buildings and properties above ground.

TBMs can operate up to 24 hours a day, 7 days a week with expert crews managing their operations.

A TBM crew includes around 10 highly skilled roles, including the TBM operator, gantry and segment crane operators, grouters and support roles. All crew members receive specialised training, including spending time inside a special hyperbaric chamber to learn about working in pressurised conditions.

In a world first, one of the crews operating the TBMs for SRL East will be an all-women team.

The all-women crew will have a range of roles – each of which requires a specific skill set. All crew members well be suitably trained and qualified to perform their roles as part of this world-first initiative.

Tunnelling will start in 2026, and the all-women crew is expected to be tunnelling by 2027. At least 10 per cent of total labour hours on the southern section of the SRL tunnels will be worked by women.

TBMs will start tunnelling the 26km of twin tunnels between Cheltenham and Box Hill from 2026, launching from sites at Burwood and Clarinda.

The TBMs for SRL East will travel up to 90m a week, depending on the ground conditions.

Trains will be taking passengers in 2035.

Once tunnelling on SRL is completed, the TBM have been designed to be disassembled from within the tunnel and brought to the surface. The TBM shield will remain in the ground.

Where possible, TBM parts will be recycled and re-used.

Work sites

About Burwood

About Clarinda

About the TBMs

FAQs

Sign up for updates