Due to the delay in tunneling in various stretches of the Phase II network, Chennai Metro Rail will shortly procure three additional tunnel boring machines (TBM) to speed up works. In the 118.9-km Phase II project, 23 TBMs are deployed at present. This corridor has the maximum length of underground network at 26.7 km in the Phase II project. The need to get more TBMs for the Phase II network was due to the inordinate delay in the tunneling operations. But officials said the work was progressing well, and tunneling work would pick up pace when the additional TBMs are deployed.