A 21-kilometer tunnel is under construction between the Bandra Kurla Complex and Shilphata for the Mumbai-Ahmedabad Bullet Train Project. Of the total length, 16 kilometres will be excavated using three Tunnel Boring Machines (TBMs), while the remaining 5 kilometres will be constructed using the New Austrian Tunnelling Method (NATM).

To construct the 16-km section with TBMs, 76,940 segments will be cast to form 7,441 rings. Special ring segments are being cast for the tunnel lining, each ring comprising nine curved segments and one key segment, with each segment being 2 meters wide and 0.5 metres thick.

High-strength M70 grade concrete is being used to ensure superior structural integrity and long-term durability. The casting and stacking yard, covering an area of 98,898 sqm (9.9 hectares) in Mahape, Thane district, Maharashtra, is currently being commissioned. The yard will feature nine sets of moulds, each containing ten pieces. Four sets of these moulds are already being installed on-site.

The yard is equipped with various cranes, gantries, and machines to automate and mechanise the casting operations, ensuring high-quality assurance during the casting and stacking of the segments. Additionally, the facility will include casting sheds, a stacking area, a batching plant, and a steam curing area.