Police are trying to trace a thug who punched a female ticket inspector in the face in an "unprovoked" attack.
The man reportedly became agitated after being asked to show a ticket at Manchester Piccadilly station on July 19.
Sickening CCTV captured the moment he hit the member of staff in the face before walking away.
The man was seen briefly chatting to the ticket inspector before he lifts a young girl over the barriers - in the process knocking the youngster's head.
He then gestures at people behind him to follow him before suddenly swinging at the ticket inspector and punching her in the face.
He then casually turns around and squeezes through the barrier before picking the girl up and walking off.
British Transport Police said the rail worker suffered bruising and swelling and was signed off work after the incident, which happened around 11am.
A BTP spokesperson said: "A man is reported to have become agitated after being asked to show a ticket.
"He lifted a child over the barriers, in the process knocking her head, and then turned to the staff member and punched her in the face.
"The staff member suffered bruising and swelling and was signed off work for a period of time."
Manchester Piccadilly station's Twitter feed also tweeted: "Please can we have your help with retweeting this to identify the man involved in this horrific attack at Manchester Piccadilly."
Anyone who recognises man in the footage is urged to contact police immediately.
They ask that anyone with information contacts BTP by texting 61016 or by calling 0800 40 50 40 and quoting reference 201 of 19/07/19.