The carcasses of the three elephants, which were moved down by a speeding train near Ettimadai on the outskirts of the city on November 26 were cremated on Saturday, at a distance from the spot, after post-mortem.
However, one of the elephants was found to be pregnant and the body of the calf was removed during the post-mortem, police said.
Meanwhile the loco pilot and his assistant were questioned by the Railway police and forest department officials, during which the driver reportedly said that he had tried to stop the train and also scare away the animals.
The forest department would take action under the Wildlife Protection Act if the Mangaluru-Chennai Express train was found to have violated the speed limits while moving through the particular spot, they said.
Meanwhile, CPI(M) MP, P R Nataajan demanded to know about the report of inquiry by Railways, when similar deaths occured at the same track a few years ago.
Wildlife enthusiasts also requested the Railways to take steps to prevent such incidents in future, as eight elephants had died in the last five years on that track.