Why Coromandel Express crashed in Odisha
Context- Minister for Railways Ashwini Vaishnaw has said that interference with the “configuration” of the track led the Coromandel Express to smash into the stationary goods train from behind at Bahanaga Bazar in Odisha’s Balasore on Friday evening.
(Credits- Visual Dictionary Online)
What is meant by ‘interlocking’ in railways?
- Interlocking in railway signalling systems is a crucial safety mechanism that ensures train movements continue without any conflicts, thus preventing accidents.
- There are three main components of the interlocking system: point, track occupancy sensing devices, and signal. The interlocking system coordinates the functions of these three components to control train movements.
- The digital interface of this system is a computer screen (or multiple screens) that shows the full view of the station layout, the real-time movement of trains, the signals, and the position of the points. This computer interface is called a data logger.
What is the function of each of these three main components?
- Signals (which are lights of green, red, and yellow colour) are installed along the tracks to indicate the status of the track ahead.
- Track circuits are electrical circuits (also known as track-occupancy sensing devices) that detect the presence of trains.
- Points allow trains to change tracks. The Coromandel was supposed to go through Bahanaga Bazar on the ‘Up’ main line, but the point just before the station switched the express on to the loop line that was occupied by the stationary goods train.
And how do the points work?
- The points, also called switch rails, are movable rails that are typically placed at the point of divergence of two tracks going to different directions.
- Once the direction of a train is determined, the point gets locked at a particular position, and cannot be budged until the train has passed. The driver, or loco pilot, has no say in this matter.
How does the system sense whether a track is occupied?
- There are various kinds of track-occupancy sensing devices. Generally, sensors are installed on the tracks that detect the passage of wheels on the rails. These are called axle counters. They count how many sets of wheels or axles have passed over them in order to determine whether the entire train has passed through.
How is this whole system configured?
- A ‘sound logic’ of what is safe train operation is fed into the interlocking system, which is controlled remotely from the station.
- Earlier, when technology was more basic, this job would be done manually, wherein a pointsman would physically operate the point to change its direction for an incoming train, and to lock it.
- Today, out of the 7,000-odd stations in the Indian Railways network, only around 100 small stations still have manual levers to control these points. The rest operate electronically
How safe is this system?
- If any of the three components (signals, points, and track occupancy sensors) does not correspond to the overall ‘safe’ logic fed into the computer, the system will work to stop the oncoming train.
- This means if the point is not locked, or not set to the desired direction, and/ or if the sensing device detects that the track is not clear, the signal will automatically turn red — indicating to the oncoming train that something is wrong and that it should stop.
Who operates and monitors the interlocking signalling system?
- The interlocking system is usually operated and monitored by trained personnel from the signalling and telecommunications department in Railways, often known as ‘signallers’ or signal operators.
- They are responsible for setting the signals, monitoring track circuits, and ensuring the safe movement of trains.
How are these systems secured against interference?
- The relay room — which is the place from where the entire interlocking/ signalling apparatus can be controlled or manipulated — is locked with double locks. One key is with the station master; the other is in the custody of the signalling staff.
- To open the relay room for any maintenance the station master’s approval is required, and every entry and exit is logged in a register.
- As technology improved over the years, the Indian Railways put in place a system in which the opening and closing of the relay rooms were connected electronically to the data loggers. Every such event is not only registered on the servers, but it also triggers an SMS that goes to the officials concerned.
Can this system be tampered with?
- The system is designed to be fail-safe. However, as Railway Board Member (Operations and Business Development) Jaya Varma Sinha said on Sunday, any machine is “prone to failure even if it runs smoothly 99.9% of the time”.
- Railway operations and maintenance is replete with instances wherein signal maintainers at stations have been found trying to bypass the system locally to rectify what they believe would be minor jobs that could be done without accessing the relay room.
Conclusion- The safe running of trains takes place in accordance with a ‘sound logic’ that is fed into the electronic ‘interlocking system’. The various components of the system work in tandem, and if any one of them becomes non-compliant with the overall sound logic, the train is supposed to be brought to a halt.
Syllabus- GS-3; Science and Tech
Source- Indian Express
