Tunnel Driver

In a recent record created, led by L&T-STEC JVs Tunnel Construction Head Palwinder Singh, Mumbai Metro Line 3 witnessed the second of two 6.65 m (21.8 ft) diameter Robbins Crossover XRE TBMs make its third and final breakthrough. The first machine made its final breakthrough in late April. Unpredictable terrain and high-pressure water ingress, amid the government-imposed lockdown due to the COVID-19 pandemic, were some of the hurdles the men at work had to overcome. The two custom-built machines were selected to bore parallel 2.9 km (1.8 mi) tunnels between the Cuffe Parade station and CST station, breaking through into several station sites along the way. Furthermore, for the first time in India, dual mode, crossover type TBMs equipped with a horizontal screw conveyor and high torque and high speed cutterhead drives were used. What’s more, for the first time in India, the crossover TBMs employed a unique technique in a 554 m (1,820 ft) long section from Hutatma Chowk to CST stations. They were used in the benching of the NATM platform tunnel through basalt rock. With these innovations accomplished for the first time in India, evidently, this victory was a true ‘breakthrough’ for Singh and his team.