In a 39th breakthrough for the project, The Robbins Company-made tunnel boring machine Tansa-2 took around 257 days to bore 1,117.5 long tunnel using 745 concrete rings.

https://indianexpress.com/article/cities/mumbai/mumbai-mmrc-completes-1117-5-m-tunnelling-on-colaba-bandra-seepz-metro-3corridor-7415935/