A TRAIN passenger has captured the moment an elderly man was assaulted in a brazen attack at Wollongong station on Monday.

The incident, which reportedly left the man bloodied and bruised after he hit the concrete, happened about 8.30am.

The passenger, who preferred not to be named, told the Mercury the incident was the culmination of a series of exchanges between a group of teenagers and elderly passengers on board the Sydney-bound train.

The teens entered a quiet carriage at Dapto station and were repeatedly told by an elderly female passenger to lower their voices, he said.

The passenger said  “push and pull” contact was made between two teenagers and the man as the train arrived at Wollongong station. 

Another scuffle ensued near the station’s entry, when the man reportedly tried to stop the teenager. 

“The teenager punched the man [and] he fell and knocked [himself] on the steel post,” he said. A loud noise was heard on impact.

The Mercury has provided police a copy of the video.