Kolkata: The city’s Purple Line has achieved a milestone with the Commission of Railway Safety (CRS) allowing trains to run on the advanced CBTC signalling mode. This will pave the way for improved train operations on the 8.3-km elevated stretch. The Purple Line, currently running every 21 minutes, can increase the frequencies to 8-10 minutes.The advanced communication-based train control (CBTC) signalling system, which is currently in operation on the East-West Metro or the Green Line.The regulatory nod from CRS, the autonomous body under the ministry of civil aviation, transitions the stretch from outdated manual or fixed-block operations to a digitally synchronised transit network. It will significantly elevate passenger safety, route capacity and operational efficiency, which essentially translates to more frequent services.The Purple Line, now running 8.3 km from Joka to Majerhat, has huge potential considering that it links the city with the southern fringes. Currently, Rail Vikas Nigam Ltd (RVNL), tasked to implement most of the city’s metro projects, is implementing the Majerhat to Esplanade section, 5 km of which is underground. The first tunnel borer, Durga, broke into the underground Victoria Memorial station last Friday. The Purple Line will eventually expand beyond Joka to Diamond Park in the south and the Eden Gardens in the north and cover 18 km.With the approval from the Commission of Railway Safety (CRS), northeast frontier circle Sumeet Singhal, clearing CBTC operations, “from Joka station to Majerhat buffer end”, the Purple Line is set to join the elite club of metro systems running with automatic telecommunications signalling.The automatic CBTC system tracks trains via wireless radio. It prevents collision and safely runs the rakes through an invisible moving block of safety space around each train. “Think of traditional train tracks like a fixed parking lot. A train must wait until the entire lot ahead is clear. CBTC works like a smart highway. The trains talk to a central computer or the operation control centre (OCC), installed inside the Majerhat station, to know exactly where every other train is positioned. This allows trains to run closer together without the risk of crashing. Thus, more services can be accommodated with shorter intervals,” an engineer explained.The Purple Line currently has three Medha rakes upgraded with CBTC functions. Metro Railway, which runs the city’s rapid transit system, is supposed to get 10 CBTC-compliant rakes in the next one year and another 50 in the following four years for Purple, Orange and Yellow lines.
