Bullet train project: Tunnel work in Mumbai
By Arun Kumar Das
New Delhi, Apr 13: On the country’s first Bullet Train Project, assembly of second tunnel boring machine has commenced at Sawli near Ghansoli in Mumbai.
The project is to establish a Bullet Train corridor between Mumbai and Ahmedabad.
The gantry weighing 190 metric tons, having a length of 18 meters, 10 meters width and 9 meters in heights have been lowered, according to railway officials.
There are a total 4 gantries in both the Tunnel Boring Machines (TBMs) which will be attached to the main shield assembly and cutter head.
The gantries will travel the complete excavated length as part of the TBM while supporting the critical operations such as excavation, waterproofing, tunnel lining segment installation etc.
Due to the space restrictions in Sawli shaft, assembly of TBM at 39 meters below ground is meticulously planned.
TBMs initial drive is expected to commence in July 2026.
TBM 1 will start from Shaft 2 at Vikhroli and will move towards Shaft 1 of Mumbai Bullet Train station at BKC while TBM 2 will start from Shaft 3 at Sawli and move towards Vikhroli (graphic attached).
The two TBMs, weighing 3080 tons (TBM-1) and 3184 tons (TBM-2) respectively, are the most advanced tunnelling machines deployed in the country. These advanced TBMs, based on Mix Shield / Slurry technology, are specifically designed to operate in complex geological conditions.
Each TBM measures 95.32 metres in total length and comprises several critical components, including the cutter wheel, main bearing, jaw crusher, erector, main shield, tail shield, and four specialized gantries that support tunnelling operations.
These machines can operate at a maximum cutterhead speed of 4 RPM (revolutions per minute), with a maximum excavation rate of 49 mm per minute, enabling steady and controlled tunnelling progress while maintaining high safety standards.
