Kolkata Metro's East-West Corridor reached a historic milestone as the Communications-Based Train Control (CBTC) signalling system work commenced for the entire stretch from Howrah Maidan to Sector V. This marks a major step toward linking Howrah with Sealdah, two of the busiest stations on Eastern Railway. The project overcame challenges, including the Bowbazar tunneling crisis, and successfully connected Sealdah and Esplanade Metro stations. In addition, the electrical works related to the aluminium third rail are nearing completion, with the electrical inspector scheduled for a statutory inspection before the rail is charged. Kolkata Metro Rail Corporation Ltd. (KMRCL) had requested a complete traffic block on two Sundays (January 12 and 19), which was granted to facilitate the work. The East-West Metro, also known as the Green Line, promises to reduce travel time by 90 minutes for daily commuters currently relying on overcrowded buses or taxis between Howrah and Sealdah. KMRCL has also submitted a request for a full closure of Green Line service from February 8 to March 24, though this has not yet been approved. The Green Line is the first corridor to implement the CBTC signalling system, enabling safe and automatic train operations. In addition to automatic train protection (ATP) to prevent accidents, the system allows trains to operate in Automatic Train Operation (ATO) mode. The system ensures trains communicate their position, speed, and acceleration, with the driver acting as an observer, only responsible for closing doors and starting the train under normal conditions. In emergencies, like earthquakes, a single button press at the control centre can stop all trains simultaneously, a feature unavailable on the existing North-South Corridor. Similar systems in London and Moscow operate with a 90-second headway, which is not achievable with traditional signalling systems. Currently, the East-West Metro is operating in two parts: Green Line-1 (Salt Lake Sector V to Sealdah) and Green Line-2 (Esplanade to Howrah Maidan). A missing link between Sealdah and Esplanade, caused by the Bowbazar cave-in five years ago, was finally resolved in December. The completion of CBTC signalling work will integrate the entire corridor into a single unified system, unlike previous stages that were treated as separate parts. KMRCL has requested a 45-day block to validate the newly installed software and make necessary adjustments if required. Before commissioning Green Line 1’s 5-km stretch, five rakes underwent 10,000 km of trials and over 1,000 tests to ensure safety certification. Similar trials will be conducted across the entire stretch with the revised software, ensuring the system’s reliability. Once the system's safety and reliability are confirmed, the entire setup will undergo an inspection by an Independent Safety Assessor (ISA) for final approval. After receiving certification, the Chief Railway Safety Commissioner will conduct a statutory inspection before granting permission for the commercial use of the full corridor. (ET)