The incident occurred around 1 p.m. at the UMSL South Transit Center in the 7700 block of Natural Bridge Road. The passengers were in the last car of the westbound train, which was approaching the station.
According to Sgt. Ben Granda, a spokesman for the St. Louis County Police Department, three officers--one uniformed and two plain clothed--were on the train at the time. Police are investigating.
The passengers were treated at the scene for minor lacerations.
Anyone with information is asked to contact the St. Louis County Police Department at 636-529-8210 or CrimeStoppers at 866-371-TIPS.
KPLR 11 News will have more information on this story as it becomes available.