A new Broad Gauge railway line from Obulavaripalle to Venkatachalam which includes construction of roadbed from KM 17/0 to 35/0, including the construction of two tunnels with ballastless track and earthwork in formation, major and minor bridges covering Kadapa and Nellore districts of Andhra Pradesh. Most of the alignment crosses the Eastern Ghats. This project consists of two Railway tunnels at chainages 18.660 to 19.600 (length 0.94 KM) and 23.370 to 29.990 (length 6.62 KMs) which form the most significant components of the contract. The New Austrian Tunneling Method (NATM) is adopted for construction of this tunnel, which employs a cyclic sequence of excavation, immediate installation of a primary support made of rock bolts and reinforced shotcrete (outer lining), and delayed installation of a secondary lining made of cast-in-situ concrete, is to be used to build the entire length of the tunnels (inner lining). Similar protective techniques must also be used to stabilize and protect the slopes of deep cuts and tunnel approaches.