The four were part of a herd that had been crossing the railway tracks as the train approached late on Saturday, about 110 miles from Guwahati, in the state of Assam.
A fifth elephant was seriously injured.
The train had been travelling from Guwahati to Silchar and, while its engine had derailed, no passengers were injured, according to regional railways spokesman Pranav Jyoti Sharma.
India has nearly 30,000 elephants and, as of a 2011 census, Assam was home to around 5,600 of them.
The tracks cut across corridors used by the elephants as they move through the hilly forest state.
With increasing deforestation and building activity close to their habitats, many elephants are forced to go further afield in the search for food. Speed restrictions have been introduced on some routes for this reason but it is not clear whether Saturday night's crash happened in one of these zones.
Mr Sharma told the Times of India that, although an investigation had been ordered, the train appeared to have been "within its stipulated speed".
Mr Sharma said 200 imminent train-elephant collisions had been prevented this year alone.
He told the newspaper: "It is only because of the close co-ordination between field level officials of both the forest and railway department that many elephants were saved." Coppied
