It's getting done slowly and quietly, deep under the city, 24x7 with deft precision. Monitored by a team of officers, workers, and German engineers, about 10 metres of the path of Mumbai's first underground railway, Metro III, is almost ready since the first Tunnel Boring Machine S-1073 begun functioning at Naya Nagar, Dharavi from November 9. The neighbouring machine S-1074, which will bore a parallel line, is still getting ready and will start action in few days. The TBM runs at a speed of 1 to 4 metres a day, and will take about 11 months to reach Dadar near Sena Bhavan, where it will be taken out. The same set of machines will then be brought back to Naya Nagar to start tunnelling on the other side towards Dharavi. There are set protocols and deadlines in place.

The TBM at Naya Nagar. Pic/Suresh Karkera