Five elephants were killed on the spot late on Wednesday night while two others succumbed to their injuries in the morning, divisional forest officer (wildlife) Sunita Ghatak said.
A herd of elephants was crossing the railway tracks while going from Moraghat forest to Diana forest on Wednesday night, when two baby elephants got trapped on the tracks, she said.
When other elephants came to the rescue of the baby elephants, a goods train which was passing through at that time hit them, killing five elephants on the spot and injuring three, the DFO said.
While two of the injured animals succumbed to their injuries on Thursday morning, another elephant is injured, she said.
Movement of trains on the track which connects New Jalpaiguri with Assam was suspended till Thursday morning as another herd of elephants was guarding the dead and injured elephants, the DFO said.
Three months ago, another elephant was run over and killed by a train near the same spot.
Speeding trains often hit elephants in the area as the railway line crosses the elephant corridor, forest officials said.
Railway officials have been requested a number of times to restrict the speed limit of trains plying in the area to 40-km/hr for the safety of the elephants, they said. The forest department has lodged an FIR under the Wildlife Protection Act against the railways alleging that the train was running at about 70 kmph, violating the speed restriction of 25 kmph to 40 kmph in the area.
"The question of speed restriction does not arise since the train was not passing through the elephant corridor," Alipurduar divisional railway manager Sachhidanand Sinha said.
The elephants suddenly appeared on the track and the driver could not stop the train, he said.
However, Forest Minister Ananta Roy said the railways were not cooperating with the forest department "as it is insensitive to the issue."
The principal chief conservator of forests Atanu Raha said the railways had been time and again requested to restrict the speed of the passing trains to 20 kmph in the elephant corridor, but no response had been received so far.
The train, he said, was moving so fast that it dragged an elephant over a distance of 200 metres from the spot.
Raha said accidents involving elephants had increased after conversion of the tracks from meter gauge to broad gauge.
"Elephants are intelligent. When the tracks were metre gauge only a couple of passenger trains ran in a day which the elephants knew about and they avoided the tracks at such times," Raha said.
Since the tracks have been converted to broad gauge, goods trains pass through at different times of the day, which has confused the pachyderms about train timings, leading to an increase in the number of accidents on the railway tracks passing through elephant corridor, he said.
The railways on Thursday said the section through which they were crossing the tracks was not among the identified elephant corridors.
The incident took place at about 10.56 pm on Wednesday and there was no advisory from the forest department as per rules. The railways could have done little to prevent the mishap, senior railway officials said.
"This corridor through which they were passing was not one of the identified elephant corridors where speed restrictions are in place," officials said.
"This was a big herd and had there been any advisories, loco pilots could have exercised caution," they added.
The tragedy comes against the backdrop of the railways last month presenting a Rs 7 crore proposal to the West Bengal government for protecting the corridors and preventing elephant deaths.
The proposals include fencing along the tracks, constructing elephant underpass, making wider passes and uniform slopes for the free movement of the pachyderms.
