Indian Railways reached another milestone as the tunneling work got completed by Tunnel Boring Machine TBM in East-West Metro Corridor with the breakthrough of ‘Urvi’ at Bowbazar, Kolkata. With this breakthrough, the entire TBM tunneling for the Kolkata East-West Metro Project is completed. This challenging tunnel drive of 800m has been completed successfully amidst this pandemic situation following COVID-19 protocol. “The stretch was difficult for tunneling work as it had century-old buildings,” the Railway Ministry said.
The TBM has passed below Sealdah Flyover also for which vehicular movement on the flyover was closed for three days for safety reasons. After completion of this TBM drive, the tunnel boring machine ‘Urvi’ along with the other halted TBM ‘Chandi’ will be retrieved from this retrieval shaft at Bowbazar. Excavation of shaft after ensuring the water tightness of the shaft and the affected tunnel and retrieval of the TBMs are intricate activities which have to be done safely and hence will take time. After completion of entire excavation, both the TBMs will be retrieved in pieces from the shaft. The RCC flooring and roofing for the shaft area will be completed thereafter and the shaft top will be backfilled to prepare the ground for overground construction.
