Signalling, train control and telecommunication (STT) systems are modern systems that are essential for the safe and rapid movement of trains. These systems are used to direct traffic and keep trains at a safe distance from each other, as well as to ensure that they run as per schedule, thereby minimising headway, enhancing efficiency and lowering operation costs. The market for STT in India has expanded significantly in the last few years. With the operationalisation of metro systems in various cities, the STT market has grown and stands at Rs 109 billion as of January 2021.
Indian Infrastructure takes a look at the key STT technologies deployed in the urban transportation segment of the country…
Communication-based train control
With advancements in telecommunications and information technology, communication-based train control (CBTC) has become the preferred solution globally. CBTC is the highest grade of automation, designed to provide immediate status updates and control to prevent accidents in special circumstances such as sudden breakdowns and power losses. Radio frequency CBTC is an advanced version that enables continuous two-way digital communication between each train and the control centre. The latest technologies used in metro rail systems include driverless train operation and unattended train operation using CBTC signalling with moving block technology instead of fixed block technology.
Automatic train control systems
Various automation technologies used in metro rail signalling systems have been combined into a single system called the automatic train control system (ATC). The ATC system ensures significant safety functions such as proper train separation, protection against overspeed derailment, detection of broken rails, execution of interlocking rules, hazard response and work zone protection. The major components of a modern ATC system are automatic train protection (ATP), automatic train operation (ATO) and automatic train supervision (ATS).
ATP consists of subsystems that offer fundamental safety through failsafe detection of harmful conditions. It can operate and halt the train when necessary without waiting for any action to be taken by the driver even when the train is being driven manually. It provides identical protection in the case of a driverless/automatic train. It offers failsafe protection against over-speeding, collisions and other dangerous conditions through functions such as train detection, train separation and interlocking. In case a train’s speed exceeds the permitted speed, the ATP system applies an emergency brake to bring the train to a halt. Some of the notable metro projects that have deployed ATP technology are the Bengaluru Metro Rail Project Phase I, the Chennai Metro Rail Project, the Mumbai Monorail Project Line 1 and the Pune Metro Rail Project.
ATO is a system that enhances operational safety by focusing on automation of train operations, whereby a train is controlled automatically without a driver’s intervention. However, most ATO systems include a driver to limit the risks that can arise from failures or emergencies. The core functions of an ATO system include automatic speed regulation, automatic station stopping, and train and platform door control. The ATO system automatically receives safety directives from the ATP system and other operational details from the ATS system for running the train in an efficient manner. Among the metro projects that have installed ATO systems are the Bengaluru Metro Rail Project Phase I, the Chennai Metro Rail Project and the Kolkata North-South Metro Project.
ATS technology monitors and adjusts the train system to ensure that it adheres to the specified schedule and traffic pattern. It helps to mitigate disruptions arising due to system abnormalities and equipment malfunctions by performing tasks such as supervision of train status, automatic routing selection, automatic operations logging and ensuring coordination to enable better train management. In September 2020, the Delhi Metro Rail Corporation took a major step towards the development of an indigenously built CBTC-based signalling technology with the launch of the first indigenously developed signal system, i-ATS. The i-ATS will significantly reduce Indian metros’ reliance on foreign suppliers and their expensive signalling systems.
Future opportunities
There are currently a large number of light rails, MetroNeo and regional rapid transit system stretches in the pipeline. By 2025-26, these projects will offer a cumulative opportunity of Rs 129 billion in the STT space. Of this, an investment of about Rs 87 billion is expected in the signalling market, while the telecom market offers an opportunity to the tune of about Rs 42 billion. With the continuous development of urban transit systems, it is imperative to design and install modern signalling and telecommunication solutions that are safe, dependable and efficient in order to ensure the safety of the mass transit systems, and those who commute through these systems.