A train carrying about 1000 passengers in India took them on an unexpected journey.
India's railway ministry says a "ghastly" accident was narrowly avoided after 22 carriages became detached from the engine and ran backwards.
The runaway carriages in Odisha, eastern India, rolled for 12km before being halted by rocks placed on the tracks by railway staff, AFP reports.
None of the passengers were injured, a railway spokesman, JP Mishra, said.
Seven railway employees have been suspended and an investigation launched.
Authorities believe that brakes applied when carriages are detached or attached to the engine were either incorrectly used or overlooked, AFP reported.
"Something ghastly could have happened and it was averted by alert staff.
"Safety cannot be compromised," Mishra told AFP, adding "more heads are likely to roll".
"Everybody in the railways (ministry) is aghast and shocked."
In social media video footage, the carriages are seen speeding past a railway platform as onlookers yelled at passengers to pull the train's emergency brake.
India's rail network carries 22 million passengers daily on some 9000 trains.