Uttar Pradesh Metro Rail Corporation (UPMRC) managing director Sushil Kumar said, “The TBM will operate in automatic mode, which is quite interesting, as the machine operates several feet deep into the ground and there is little room for any error.” The route is automatically set beforehand by entering the coordinates of the location and the TBM follows that route for tunnel construction.

“While the cutter head moves forward cutting the debris and initiating the movement, the last part of the TBM, which is called the ring erector, erects ring segments in a circular motion, making a tunnel,” said a press statement issued by the UPMRC.

“This entire process is all the more interesting because there is only one window for launching the TBM, i.e. the launch shaft in the beginning and retrieval shaft at the end, and in between the movement of the TBM has to be ensured with utmost accuracy,” said the release.

The TBM usually places 10-14 rings per day and the length of each ring is 1.4 m; thus, it moves a distance of 14-20m per day.

There are seven underground stations for Agra Metro Rail Project which will use TBM machines for tunnel construction.