Herman Susanto and Dwi Aksan were heading from Indonesia’s capital Jakarta to the satellite city of Cikarang after a long day at work on Monday when disaster struck.

Susanto, the head of the Indonesian Workers’ Federation, and his colleague, Aksan, were in the third carriage of a commuter train crammed with workers going home at around 9pm when it stopped to let passengers alight at Bekasi Timur station.

The two men had hoped to rest before they reached their final stop, but instead, they found...