Indore Metro Begins Underground Tunnelling With 1,000-Tonne TBM

A big city in India called Indore is building a special underground train system called a Metro.

To dig tunnels under the ground, workers are using a giant machine called a Tunnel Boring Machine, or TBM.

The machine is as heavy as about 1,000 tonnes and was brought from Thailand.

Right now, workers in Indore are putting the machine together, almost like building a huge robot.

When it is ready, the machine will dig under the ground near the Airport.

The giant machine works like a worm, digging through soil and rock and making about 20 metres of tunnel every single day.

While it digs, it also puts strong concrete walls in place so the tunnel stays safe and strong.

Two tunnels will be built, one for trains going in each direction.

In total, about 12 kilometres of the Metro will run underground, and finishing it will take four to five years.