Improvements in signalling and telecommunications (S&T) systems are key to increasing the efficiency of Indian Railways (IR). S&T enhances safety levels, increases line capacity on existing tracks, provides online information on operation and flexibility in yard operations, and disseminates information to passengers.
A robust telecommunications system is vital for relaying information on trains and disasters, and advertisements to passengers and aids in generating higher revenues for the railways.
Investment plans for S&T
As part of Union Budget 2017-18, Rs 1 trillion has been earmarked under the Rashtriya Rail Sanraksha Kosh (RRSK) for ensuring passenger safety. Further, an investment of more than Rs 200 billion has been planned for S&T over the three-year period 2017-18 to 2019-20. Between 2012-13 and 2016-17, an average of Rs 9.4 billion was allocated by IR for S&T works on capital account.
Further, IR is also upgrading S&T systems as part of its ongoing fixed infrastructure augmentation projects including line doubling, tripling, new lines, gauge conversion, and electrification works, among others.
The various components of S&T works to be funded through RRSK are the installation of automatic train protection systems (train protection and warning systems [TPWSs] and traffic collision avoidance systems [TCASs]), the upgradation of interlocking systems, replacement of signals, centralised online monitoring and predictive maintenance, and the provision of mobile train radio communications, optic fibre cable (OFC) and quad cables on IR. An investment of Rs 101.4 billion has been projected for all the components, with funds amounting to Rs 27.5 billion for TPWS and TCAS alone.
Recent plans and initiatives
Some of the recent initiatives undertaken or planned to be undertaken by IR to upgrade and modernise its S&T system are discussed below.
Electronic interlocking (EI): In railway signalling, interlocking is an arrangement of signal apparatus that prevents conflicting movements at junctions or crossings. Under EI, intricate wiring in relay-based interlocking systems is replaced by electronic logic circuit cards. This, in turn, reduces the time for and cost of installation and commissioning. Till March 31, 2017, Indian Railway Stations Development Corporation Limited (IRSDC) had provided 1,200 EI systems and another 3,000 EI stations have been planned to be set up by 2022.
EI has a number of advantages over electromechanical or conventional panel interlocking, such as reduced space requirements, self-diagnostic features, greater safety and reliability, etc. However, EI is vulnerable to lightning and surges, and the non-user-friendly diagnostic tools, flow charts and event/error logs make it extremely difficult to reduce the mean time to repair (MTTR). Also, the annual maintenance cost to the original equipment manufacturer does not ensure reduced MTTR due to the geographical spread of equipment as well as a lack of resources on site.
TPWS: This is a train protection system which continuously checks that the speed of a train is compatible with the speed permitted by the signalling system. In case of a discrepancy, the automatic train protection (ATP) activates an emergency brake to stop the train. IRSDC is in the process of deploying proven ATP systems to avoid train accidents/collisions due to human error resulting in “signal passing at danger” or overspeeding. TPWSs are presently being used for the Gummidipundi suburban section (Chennai) of Southern Railway (50 route km), Hazrat Nizamuddin-Agra section of Northern/ North Central Railway (200 route km), Gatimaan Express on the Delhi-Agra section and Dum Dum-Kavi Subhash section of the Kolkata metro (25 route km).
TCAS: This is an ATP system with cab signalling features suitable for speeds of up to 110 km per hour. IR has developed an indigenous TCAS which is safety integrity level (SIL) 4 certified. (SIL 4 is the highest level of risk reduction that can be obtained through a safety instrumentation system.) It has been tested for Southern Central Railway and is in advanced stages of inspection.
Remote condition monitoring of signalling gears: Traditionally, two types of signalling maintenance management procedures have been deployed – the fix-on-fail maintenance procedure and the planned time-based maintenance procedure. However, these traditional procedures lack reliability and result in high maintenance costs. In view of the high maintenance costs, IRSDC is developing a predict-and-prevent maintenance regime instead of find-and-fix. The predict-and-prevent maintenance method uses historic data to predict the occurrence of signal failures, thereby enabling condition-based maintenance, which is capable of considerably reducing the operating costs and improving productivity through uninterrupted operations.
Life cycle support in electronics: Under this concept, a suitable provider is identified for developing a long-term partnership on a build-operate-own-transfer model. The provider is required to create the designated infrastructure as a pilot project and has to run a comprehensive training workshop. Besides, the provider will help in component-level repair of printed circuit board assemblies and repair of complete electronic units/modules, redesign infrastructure to meet component and sub-assembly obsolescence, identify and source obsolete and hard-to-find components and sub-assemblies, and undertake skill development of staff on a long-term basis.
Block proving axle counter (BPAC): The BPAC is a system used for controlling the movement of a train in the block section, working on the absolute block working principle. It has been designed to replace existing block instruments used in railway signalling systems. The system indicates the arrival of the train without any human intervention (this is presently ensured by the stationmaster).
The way forward
The key issues and challenges in the operations and maintenance of the S&T system include providing increased levels of system availability, improving maintenance and diagnostic capabilities to detect and react to signalling and train control equipment failures, utilising information technology based on the data communication network, providing a modular design to permit application to a wide range of operational requirements without requiring extensive recertification of standard safety functions, complying with international standards that support interoperability and interchangeability between trains and trackside, and ensuring minimum installation time. These issues need to be urgently addressed for smooth operations and passenger safety.
Going forward, IR’s primary focus will be on deploying smart signalling systems such as automatic signalling, EI and interfaces, centralised traffic control and train management systems, online automated maintenance monitoring and control centres for predictive signalling maintenance, etc. Key technologies that will play a major role in the future are train operation and control systems, sensing and data analysis technologies, and intelligent signalling information network infrastructure.
Based on a presentation by Akhil Agrawal, director general, signal and telecom, Railway Board, at a recent India Infrastructure conference