A retired lieutenant colonel was trampled to death by a domesticated elephant of the state forest department on Thursday afternoon during the testing of AI-based systems that can prevent train-elephant collisions.

Noida-based Sandeep Choudhury, 57, was at the site representing a private technology company — one of three competing for the contract to install the intrusion detection system (IDS), which can detect animal movement near the tracks.

The retired soldier was attacked close to the tracks after the IDS demos had been conducted successfully in front of senior Northeast Frontier Railway (NFR) officials near the Alipurduar Junction, in a part of the Buxa Tiger Reserve.

Choudhury was taken to the Alipurduar district hospital where doctors pronounced him dead.

Over 80 elephants have died since 2003 after being hit by trains on the Dooars stretch of the NFR that moves through reserve forests and wildlife sanctuaries.

To prevent such deaths, the NFR had in 2022 installed an IDS on an experimental basis along a 74km stretch of tracks between Siliguri Junction and Alipurduar Junction. With the experiment a success, the NFR decided to install the IDS along other stretches, too, and invited the three bidders to demonstrate their respective IDS mechanisms on Thursday.

“Today, the GM (NFR general manager Chetan Kumar Shrivastava) and other officials came to Alipurduar to check out the systems’ effectiveness,” a source in theNFR said.

“Representatives of all three companies that had participated in the tender were present to demonstrate the technicalities. The exercise was undertaken to select the company that will be assigned the job.”

One of the companies — it’s unclear whether it was the one Choudhury was representing — had arranged for two kunki (domesticated) elephants, Jonaki and Mumtaz, to be brought for the demo.

Shrivastava, Amarjit Gautam -- divisional railway manager of NFR’s Alipurduar division --- and other officials had arrived at Madhu Gachtala, a locality within the Buxa Tiger Reserve that is around 10km from Alipurduar town, to watch the demos.

About 1.30pm, with the exercise over, the railway officials and others began heading to the nearby road where their vehicles were parked. But Choudhury lingered on the other side of the tracks, close to the two elephants.

Just then, the Alipurduar-bound Kanchankanya Express rumbled through the spot. A forester said the train’s repeated honking seemed to irritate Jonaki. As the elephant turned aggressive, the mahout alerted Choudhury to move away.

Initially, Choudhury seemed not to pay attention and began running only after the elephant chased him. But he slipped and Jonaki trampled on him, the mahout unable to control the animal.

After the train had passed, the mahout raised the alarm and guided the agitated elephant away fromthe gathering.

“It’s an unfortunate incident. A kunki elephant fatally injured him,” Shrivastava said.

Railway sources said they were in touch with Choudhury’s company and would “extend all necessary help to them and the family”.

Shrivastava said: “The IDS system was launched in the region experimentally in October 2022. Since then, there hasn’t been a single elephant death along thatparticular stretch.”

The AI-and-sensor-based system sends signals to nearby railway stations and control rooms if it senses movement by elephants or other wild animals near the tracks. Railway staff pass the information on to the loco pilots, who slow down and take precautions against hitting the animals.

“We will install the IDS along a stretch of 430km across NFR. A sum of ₹110 crore has been allotted for the project,” Shrivastava said.