Alice has left Burwood: inside the Suburban Rail Loop's first tunnel drive

Somewhere under Melbourne's east right now, a machine the length of a city block is grinding south-east through the ground at about a centimetre a minute, and roughly twenty-five people are inside it.

Her name is Alice. She is the first of eight tunnel boring machines on Suburban Rail Loop East, and on 7 September the Victorian Government confirmed she is properly away — tunnelling from Burwood toward Glen Waverley. A second machine, Hacia, is already in the ground and will start the parallel tunnel within weeks.

After four years of hoardings, traffic changes and very large holes, this is the bit where the Suburban Rail Loop starts to become an actual tunnel.

What a TBM actually is, which is stranger than it sounds

Calling these things machines undersells them a bit. A tunnel boring machine is closer to a factory that happens to move.

Alice and her sisters are between 100 and 150 metres long, with a cutterhead just over seven metres across — about the height of a two-storey house, standing on its end and spinning. Webuild puts Alice at around 103 metres with a 7.25-metre cutterhead.

The front does the digging. Everything behind it is the support act: the machinery that pushes the whole assembly forward, the system that carries spoil out, and the arm that lifts curved concrete segments into place and bolts them into a ring. The tunnel is built continuously, immediately behind the digging. There is never a moment where there is just a hole.

And people live in there, in shifts. Each TBM runs 24 hours a day, seven days a week, with up to 25 people aboard — a pilot who actually drives the thing, tunnel engineers, electrical engineers, crews handling the segments. There is an office. There is a kitchen. There are toilets. When the government's own fact sheet describes them as underground factories, it is being fairly literal.

A good week is about 100 metres.

They also run on 100 per cent renewable electricity, which is a slightly surreal detail to sit alongside "grinds through rock".

The launch was the awkward part

Getting a 100-metre machine into the ground requires somewhere to put a 100-metre machine, and Burwood does not have that kind of room.

So the crews used what is called an umbilical launch. The front section goes into the ground and starts tunnelling on its own, with the rest of the machine assembled progressively behind it as space opens up — trailing gantries fed in and connected as the cutterhead advances. The machine builds itself into the tunnel it is digging.

It is a standard technique on constrained urban sites, and it is the reason tunnelling could start at Burwood at all rather than at some more convenient paddock.

Eight machines, named by seven primary schools

Tunnel boring machines are traditionally given women's names, a superstition that runs back to the 1500s and the practice of miners praying to St Barbara, patron saint of tunnellers, for protection underground. Nobody in the industry seems inclined to break the tradition, on the reasonable grounds that why would you.

For SRL East, the naming was handed to Grade 1, 2 and 3 students from seven primary schools along the corridor — Clayton North, Clayton South, Essex Heights, Huntingdale, Kerrimuir, Le Page and Roberts McCubbin. They voted from a shortlist of Victorian women.

Here is who they picked:

Elizabeth Chong's response to being told about it was one of the better quotes to come out of an infrastructure project: of all the honours in her career, she said, this one was a thrill — especially because children chose her.

The kids who named them will be somewhere around their late teens when the line opens.

Issy, and a genuine world first

The Issy entry is worth pausing on, because it is not honorary in the usual sense.

Isolde Piet is the world's first female TBM pilot. She is also SRL East's construction manager for tunnels on the southern package, and she will lead the southern tunnelling crews — including what is being described as the world's first all-women TBM crew.

So there will be a machine named after her, on the job she is running, tunnelling toward Cheltenham.

Where they are all going

SRL East is 26 kilometres of twin tunnels between Cheltenham and Box Hill, with six new underground stations: Cheltenham, Clayton, Monash, Glen Waverley, Burwood and Box Hill. It connects Monash and Deakin universities by rail for the first time.

The work is split into two tunnelling packages, and the machines are paired accordingly:

North — Glen Waverley to Box Hill, about 10 kilometres, built by Terra Verde, a joint venture of Webuild, GS Engineering and Construction, and Bouygues Construction Australia. Contract value around $1.7 billion. Alice and Hacia are running Burwood to Glen Waverley now; Elizabeth and Bich-Cam follow from Burwood toward Box Hill. The scope also includes 39 cross passages between the tunnels, two station boxes, two access shafts and a ventilation shaft.

South — Cheltenham to Glen Waverley, about 16 kilometres, built by Suburban Connect, a consortium of CPB Contractors, Ghella and ACCIONA. Contract value around $3.6 billion. Aayushi and Belinda work the Glen Waverley to Clarinda stretch, with Aayushi being assembled at Clarinda to launch this year. Issy and Muriel take Clarinda to Cheltenham, launching in 2027.

There is a nice bit of provenance in the hardware, too. The four southern machines are Herrenknecht. Two were built new in Guangzhou — and the other two are veterans, rebuilt at Herrenknecht's Newcastle facility after finishing their working lives on Sydney Metro. The four northern machines are CREG, built in Zhengzhou.

What it is like from up top, which is mostly: nothing

The tunnels generally sit 20 to 40 metres down, dipping to about 60 metres at the deepest point — roughly a 16-storey building, underground. The stations are much shallower, between 15 and 30 metres below street level, deliberately kept close to the surface so passengers are not spending four minutes on escalators.

At those depths, most people above the alignment will not notice anything. Noise, vibration and ground movement are monitored continuously, and properties directly above the route are offered a condition survey before the machines arrive — which is standard practice and also the sort of thing worth taking up if it is offered to you.

Then there is the spoil. SRL East will generate around 3.5 million cubic metres of excavated rock and soil.

The handling of it is more elaborate than most people would guess. Material comes out on enclosed conveyors into purpose-built acoustic sheds, where it sits in enclosed bins. Trucks are loaded inside the shed, then washed, weighed, covered, GPS-tagged and fully sealed before they touch a public road. The tagging means every load can be traced to where it ends up. Soil is tested and managed under EPA requirements.

If you have ever followed a spoil truck out of a tunnelling site and wondered why nothing falls off it, that is why.

The numbers, plainly

The 2021 business case put SRL East at $30 billion to $34.5 billion, opening in 2035. The Victorian Government has committed $11.8 billion across successive budgets. The Commonwealth's contribution now stands at $6 billion — $2.2 billion originally, plus a further $3.8 billion announced in May 2026.

More than 3,000 people were working on the project as of early this year.

The project has attracted plenty of argument about whether the benefits justify that, and Infrastructure Australia and the Victorian Parliamentary Budget Office have both published assessments worth reading if you want the full picture. That debate is real, and it is not this article.

What is not in dispute is that the machines are in the ground and turning.

What happens next

Alice keeps heading for Glen Waverley. Hacia starts the parallel bore within weeks. Aayushi launches from Clarinda before the end of the year, and 2027 brings the rest — Burwood toward Box Hill, and Heatherton toward Cheltenham.

Between now and 2035 there is an enormous amount of work that is not tunnelling: 39 cross passages on the northern package alone, station boxes, fit-out, track, signalling, testing. As Cross River Rail is currently demonstrating in Brisbane, the gap between "the tunnels are finished" and "the trains run" is measured in years, not months.

But for the next stretch, the story under Melbourne's east is eight machines, several hundred people working around the clock in shifts, and about 100 metres a week.

Reported from the Victorian Government's tunnelling announcement and SRL tunnelling fact sheet, contractor releases from Webuild and ACCIONA.

Published 10 September 2026