Three elephants died after a passenger train rammed into a herd crossing a railway line in the middle of Dudhwa National Park in Lakhimpur district, 250km from capital Lucknow in Uttar Pradesh.

"The incident took place at about 7.30 pm on Saturday," principal chief conservator of forests R L Singh said on Monday. "Among the dead were a male, a female and an elephant calf." He also said a fourth elephant, which was injured in the accident, was untraceable.

The engine of the Gonda-Mailani express train was also damaged in the accident.

Eight trains pass through this park each day and the track runs for 40km right in the middle of the national park. Incidents of speeding trains hitting animals is not uncommon.

Singh points the finger at the railways. "This was not the first incident of its kind. Our repeated requests for diversion of the rail track have gone unheeded and what is worse is that the railway authorities have also not been able to enforce speed restrictions on trains passing through the core area of the wildlife park."

The Rajaji, Corbett and Dudhwa National Parks lie in a single stretch and have a combined population of nearly 1,500 pachyderms. After Uttaranchal became a separate state, Uttar Pradesh was left with only the Dudhwa National Park, which has barely 35-odd elephants.

The Railways have remained indifferent to the much desired shifting the railway line even in the Rajaji National Park in the Dehradun-Rishikesh area, now in Uttaranchal.

According to reports, at least a dozen elephants were killed over the past decade after being knocked down by trains in this park. The elephant population in the park is estimated at between 500 and 600.