RRB Practice 2

Railway signalling is the critical engineering and operational system by which trains are safely guided along their assigned routes across the network, preventing collisions between trains on the same track and ensuring the orderly and efficient movement of the enormous volume of passenger and freight traffic handled by the Indian Railways every hour of every day. The traditional absolute block system, in which a block section of track between two adjacent stations is permitted to be occupied by only one train at a time and signals are operated manually by station masters who communicate with each other by telephone to grant and receive line clear permission, was the backbone of Indian railway signalling for most of the twentieth century but is being progressively replaced by modern automatic block signalling systems and electronic interlocking equipment that reduce human error and allow more intensive use of the track. The Kavach automatic train protection system, developed indigenously by the Research Designs and Standards Organisation in collaboration with a consortium of private industry partners under the government's Make in India initiative, represents a landmark advance in Indian railway safety technology. The system uses radio frequency identification tags embedded in the track, ultra-high-frequency radio communication between locomotive-mounted equipment and stationary units, and satellite-based positioning to create a comprehensive real-time collision avoidance network that functions regardless of weather conditions, visibility, or driver alertness. When two trains on the same track approach each other within the defined safety envelope, Kavach automatically applies the emergency brakes on both trains without requiring any action by the drivers, and the system similarly prevents a train from passing a signal that has been set to stop without authorisation, eliminating the most common cause of rear-end and head-on collisions. Alongside the deployment of advanced signalling technology, the railways is investing heavily in track geometry measurement using specialised machines that survey the precise alignment and surface condition of tracks to identify sections requiring maintenance before they deteriorate to unsafe levels, rail flaw detection using ultrasonic testing equipment that identifies internal cracks in rails invisible to the naked eye, and bridge health monitoring systems that continuously measure the structural behaviour of important bridges under traffic loading conditions. The Centre for Railway Information Systems, known as CRIS, develops and manages the passenger reservation system that processes millions of ticket bookings daily, the national train enquiry system that provides real-time information on train positions and expected arrivals, the freight operations information system, the crew management system, and numerous other digital platforms that support the commercial and operational functions of the Indian Railways across all its zones, divisions, and stations. The Unified Train Management System being progressively rolled out across the railway network is designed to give control room operators and divisional officers real-time visibility of the position, speed, and status of every train on the network, along with tools to manage traffic flows and address delays arising from operational disruptions. The integration of station, locomotive, and control room systems through digital communication networks is a key element of the overall modernisation of the Indian Railways, enabling data-driven decision-making and improving the responsiveness of the system to the operational challenges that arise in running one of the world's busiest rail networks.