Three persons crossing the track were run over by a train near the Ambur railway station on Sunday.
According to Government Railway Police from Jolarpet, Shankar, 45, from Chinna Karumbur village in Ambur taluk, his sister Bhanumathi, 50, and her grandson Nithish, 7, reached the station to board a train to Chennai.
As they were crossing the track to reach the other platform, they were run over by the Tiruvananthapuram-Chennai train. All of them died on the spot.
The railway police removed the bodies and sent them to Ambur Government Hospital for post-mortem.
Railway officials pointed out that though there was a subway, people continued to cross the track.