Featuring a Brightsandz Innovation Case study of RFID Kavach train safety (collision avoidance system)

Context

Over the past few decades, Railway collisions in India have been a significant concern. The frequency of accidents and the resulting casualties highlight the challenges faced by Indian Railway’s extensive rail network. For instance, between 2018-19 and 2022-23, India averaged 44 train accidents annually as an average. In 2021, the National Crime Records Bureau reported 16,431 deaths and 1,852 injuries related to railway accidents. In the first five months of 2024, there were 18 train accidents, averaging over three per month. These statistics underscore the ongoing safety challenges within the railway system.

Objective

In July 2020, the ministry of railways along with the Research design and standards organization (RDSO, Indian railways) has launched a Train Collision avoidance platform (TCAS) called Kawach. The objective of this activity was Preventing train collisions by using innovative RFID based collision avoidance technologies. We shall name it RFID Kavach train safety (collision avoidance system). The intent was to devise and operationalize cost effectives solutions for real-time monitoring and alerts and increasing railway safety.

Government efforts – KAWACH TCAS (Train collision avoidance system)

Kawach is an indigenous Automatic Train Protection (ATP) system developed by Indian Railways to prevent collisions and enhance safety. It uses GPS, RFID, and wireless communication to monitor train movement, ensuring automatic braking in emergencies. Kawach protects against signal passing at danger (SPAD) and maintains safe distances between trains and therefore, significantly reduces accidents and establishes a safer, more reliable railway system.

How do track based RFID Kavach train safety (collision avoidance system) work?

In a phased manner, the ministry of railways will be installing indestructible RFID tags at some intervals of railways tracks. While the trials currently involve the high-speed Vande Bharat, Shatabdi and Rajdhani trains; however, in due course of time, the total length of railway tracks in India (132K kilometres (as of 2023)) will be “RFID tagged”. These tags are mounted on the sleepers on which the railway tracks are placed.  The tags are calibrated distance wise and track wise and the data is stored in a central server.

Independently, the RFID antenna and reader set up is mounted on the lower portion of the locomotive. This captures TAG data on the tracks and saves them on a remote cloud platform. Thereby, the RFID Kavach train safety (collision avoidance system) is able to uniquely identify tracks (on which the train is running) and the specific location of the train.

At any point of time, if a TRAIN A running on TRACK 1 (identified by RFID tags) is within a “X” kilometer distance of TRAIN B running on the same TRACK 1 – alerts are sent to the authorities and the central server for corrective measures, thereby reducing / eliminating accident risks.

Shortcoming of the system and use of BRIGHTSANDZ RFID Beam forming – steering technology to address these shortcomings 

BRIGHTSANDZ is a Gurugram based EMF consultancy that specializes in RFID antenna technology and beam control solutions for specific industry use cases. We design special purpose antennas and use other innovative solutions to control RFID signal beam and its propagation.

In the KAWACH RCAS case, the RFID system mounted on the bottom of the locomotive had a beam width which was in excess of 1.5 metres (.75 metres either side). Additionally, the wide beam coupled with signal reflections from the metal interfaces (metal wheels, tracks and under-chassis of the locomotive) lead to the cross reading of RFID tags from adjacent tracks. That is, TRAIN A running on TRACK 1 was reading and signaling TRACK 2 and (possibly) TRACK 3 tags as well. Therefore, as against data of TRAIN A from TRACK 1, the central server could be reading that TRAIN A could be on any one of the tracks – TRACK 1, 2 or 3. This can be very confounding for the automatic collision avoidance system.

How Brightsandz Beam forming – steering helps in overcoming cross reading of tags on different tracks ?

The trick is to limit the dispersion width of the RFID beam, so that a large fringe area is limited into only a narrow width high focus mid region area (see illustration below). A simple example of the beam forming – steering technology is like blinders that we put on horses to limit their field of vision so as to keep the focus only on the path.

Therefore, a beam which spreads uniformly in a circular pattern is limited only to high intensity region which is limited to the areas between the limits of the railway tracks. Also beam confinement, reduces excess reflection of beams from the metal surfaces such as wheels, under carriage, rails etc. The beam does not cross over to the adjacent tracks and read those tags i.e the beam is only reading TRACK 1 or TRACK 2 or TRACK 3 tag on which the train is actually running.

Thus, the risk of cross reading tags is eliminated by the Brightsandz RFID Kavach train safety (collision avoidance system).

Laboratory results

1. In laboratory tests, the Brightsandz RFID Kavach train safety (collision avoidance system) reduced beam dispersion by 45%.
2. The beam is controlled to an area between the two rails with safety margins on both sides.
3. The high speeds reads are in 100% reliability thereof.

 Conclusion

Brightsandz beam control technology is currently in pilot with Vande Bharat trains after which it will be deployed across various other railway locomotives in India. This will enable safe train journeys, where the nasty accidents of the past will be relegated as a forgotten chapter in the history of Indian railway.

Please note that the Antenna and reader used for Train Collision Avoidance system is Zebra, the Project management and expertise was provided by Scatternet and Medha under RDSO (Research Design and Standards Organization). The technology for RFID (based) Kavach train safety (collision avoidance system) has been indigenously conceptualized, developed and made in India.