How was the tunnel through which the train passed built?

Shield tunneling is an advanced technology, but now most tunnels are constructed by traditional drilling and blasting method.

The most primitive drilling and blasting method uses a sledgehammer and a steel drill, and several holes are punched in one section according to the design. After a certain amount of explosives are filled, they are detonated by manual ignition or electric ignition, and then smoke and slag are discharged. This is a cycle. In the formed tunnel, all kinds of reinforcement and protection materials should be lined.

Later, the pneumatic drill replaced the sledgehammer, now the trolley replaced the single pneumatic drill, and the loader replaced the manual slag discharge. Tunnel construction is not what it used to be, but it is still a hard construction work.

Disadvantages such as faults, landslides, water seepage and gas should be overcome during construction. If the tunnel is too long, it is necessary to drill wells to increase the working face.

Tunnel construction is often the key project of railway and highway construction, with the most unpredictable factors, so it is the earliest to start construction.