The three students – aged between class VIII and X and staying at a shelter home in Thrissur – left the school campus at about 12:30 p.m. on Tuesday and were reported missing by school authorities.
Following the alert, police examined CCTV footage from the school vicinity and the nearby railway station, which showed the girls boarding the Ernad Express bound for Thiruvananthapuram.
Kerala police continued to monitor the train as it travelled through Ernakulam, coordinating with railway officials and alerting their counterparts in Alappuzha.
When the Ernad Express arrived at Alappuzha railway station, officers located the three girls and escorted them to safety, confirming that they were unharmed.
A case has been registered in connection with the incident, and investigators are continuing to probe the circumstances of the girls' departure from school and their subsequent travel on the train.