Intrusion Detection System: Where elephants & trains cross path, an AI-enabled system prevents accidents

“That was close. We have to be alert all the time. We cannot lose elephants. We get on average four alarms everyday,” says Sunil, referring to a recent incident in Assam’s Hojai district, where eight elephants were killed after being hit by the Sairang-New Delhi Rajdhani Express on December 20, 2025. With this, the total number of elephant deaths on railway tracks has risen to over 90 since 2019.

Binnaguri is in the middle of the 52-km Madarihat-Nagrakata section, which is among the most vulnerable elephant corridors along railway tracks in the country. This section was taken up as a pilot project to roll out an AI-enabled Intrusion Detection System (IDS) for detecting the presence of elephants.

Binnaguri is in the middle of the 52-km Madarihat-Nagrakata section, which is among the most vulnerable elephant corridors along railway tracks in the country.

Following its commissioning in 2023, the Ministry of Railways has undertaken a Rs. 208-crore project to install IDS across 1,158 route kilometres of railway tracks, spanning eight zones – Northeast Frontier Railway (NFR), East Coast Railway (ECoR), Southern Railway (SR), Northern Railway (NR), South Eastern Railway (SER), North Eastern Railway (NER), Western Railway (WR), and East Central Railway (ECR). So far, the system is working along 141 route kilometres under the NFR, including Madarihat-Nagrakata section.

“Elephants are very intelligent animals, but they have one specific behaviour because of their size, which is different from others. When the loco pilot presses the horn, the other animals quickly disperse and get off the track. But the Elephants find it difficult to return back, down the track slope. They run on the track its easy to move and offers a clear path. In such a case even if the loco pilot tries to stop the train immediately, it could collide with the elephant. This is why it’s crucial to keep an eye on elephant movements well away from the tracks,” said Sunil.

The team has to be extra cautious during 5pm-9pm, considered a danger zone, he said. Around 20 trains pass through the station in a day.

Irfan Azam, a senior section engineer, who is involved in the project since the beginning, says this is the same technology which is used on the border areas by security forces to prevent infiltration.

Binnaguri Station. (Express Photo)

“IDS is a fibre-based system which works on the principle of Distributed Acoustic Sensing (DAS). The DAS work on the principle of Rayleigh scattering phenomenon. The Laser pulses from remote OFC DAS units are sent continuously and reflected pulses are received from various points along the fibre cable and analysed. So, whenever there is an elephant movement along these optical fibre cables, it captures the signature of the elephant, based on pressure, weight and vibration or external sound waves. After the analysis of the signature, the system creates the alarm at the station and level crossing gate,” said Azam, showing the OFC room with its working server monitor.

IDS comprises three main units. The Central DAS server, installed at the Railways’ divisional office, serves as the primary processing hub. It is equipped with high-performance computing servers, storage facilities, a centralised database, software algorithms, and networking interfaces. The second component is the Remote DAS unit, which interrogates the optical fibre and receives and processes the backscatter signals generated by vibrations along the track. The third key interface is the LC gate hooter or alarm unit. It receives train-location information and alert messages from the Central DAS server and generates alarms to warn loco pilots and station staff.

“The optical fibres were already laid along the tracks. It is used for all communication purposes. However, for this project, we started laying fibres at the Railways boundary along the track. To secure 1-km of elephant corridors, we lay 2.5 km of optical fibres. For this 155-km block section of Alipurdwar to Siliguri, a 47-km stretch is in operation with elephant intrusion detection system. We have to install a total of eight DAS units on this section. One DAS channel can monitor the 30-km track, Due to this system, there have been no accidents in the last four years,” said the senior section engineer.

At the Red Bank level crossing gate on Banarhat-Carron section, along National Highway-31C, gateman Ganesh Gaur rolls down the barrier on either side of the track to make way for the goods train. Here, the 1-km section is the elephant corridor and optical fibres were laid down three years back.

“Most accidents happen because of baby elephants. I don’t remember the exact year, but around 10 years ago, six elephants were killed when I was on duty here,” says Gaur. “The incident occurred near a bridge as the herd was returning after drinking water nearby. I have a hooter at this gate to alert us about elephant movement, but the alarm goes off for every passing train.” As he speaks, traffic piles up, with people pressing him to open the gate as the train was a little late.

One of the stretches on the Madarihat-Nagrakata section with Intrusion Detection System. (Express Photo)

At times, there are false alarms as well as the system works as a weight sensor. “The system generates alerts by matching vibration patterns with an elephant’s signature. However, it could also be a group of cattle or other animals, a fallen tree, or even heavy machinery moving through the area for construction work,” says another railway official

Irfan Azam says that such incidents sometimes occur when elephants move away from their designated corridors in search of grazing, especially when paddy crops are young, green and lush.

“We are working with the forest department to install optical fibres in their land, inside the forests. We are upgrading this technology to detect the rail fractures as well,” said Azam.

According to the Ministry of Environment, Forest and Climate Change, a comprehensive report titled “Suggested Measures to Mitigate Elephant & Other Wildlife Train Collisions on Vulnerable Railway Stretches in India” has been prepared after field surveys across 127 identified railway stretches spanning a total of 3,452.4 km.

“Based on the intensity of wildlife movement, 77 railway stretches covering 1,965.2 km across 14 States have been prioritised for mitigation along with site-specific interventions…A total of 81 elephant casualties due to train collisions were reported by various states between 2019-20 and 2023-24,” said the Ministry in a written response in Lok Sabha in July 2025.