This is the step by step process showing how the construction engineering experts design and dig subway tunnels. Subway systems are important in most of the big cities as they transport millions of people everyday.

So, how are the tunnels excavated? This is Herrenknecht‘s Earth Pressure Balance. It’s 40 feet in diameter and 312 feet long. The machine dig through 1,000 feet of earth per week. Hydraulic cylinders press it forward.

After that, a rotating cutting wheel will breaks up the soil and other material. It excavates up to 97,000 metric tons of soil per week. Then the machine lines the tunnel walls with concrete segments. All so you can zip across town from one place to another destination in term of speed.