
The accident occurred around 12pm at Kaidubi-Sadardi rail crossing on Faridpur–Bhanga–Barishal highway, said highway police.
The deceased were identified as three-year-old Raihan, his mother Rimu Akter, and his grandmother Nurjahan, 50, of Purbosadardi village in Gharua union of Bhanga upazila.
Sub-Inspector Sohel Mia of Bhanga Highway Police Station said the three-wheeler was heading towards Chumurdi union from Bhanga Sadar when the speeding bus of New Modern Paribahan coming from the opposite direction hit it, leaving three people dead on the spot and injuring four others, reports.
The injured were taken to Bhanga Upazila Health Complex but their identities are yet to be ascertained, he said.
Police seized the bus and efforts were underway to detain the accused, the police official added.