The 37-year-old woman was walking near Dalmuir railway station, near Clydebank in West Dunbartonshire, in the early hours of Saturday when the “terrifying” attack happened.
The victim was approached by the man who began talking to her as they walked in the same direction.
As they made their way towards the area near Glendevon Place, the man forced the woman onto waste ground where he raped her.
The man then ran off towards the Dalmuir area.
Police said the attack took place between 1.30 and 2.30am.
Detectives are searching through CCTV footage in bid to find clues.
And they are appealing for anyone who may have seen or heard the attack to come forward.
The man is described as white, around 5ft 4in, of medium build, with fair hair and he was wearing dark coloured denim.
Extra police patrols have been launched in the area to try and reassure the public.
Detective Sergeant Gerry Shovlin, Clydebank CID, said: “The man started chatting to her and said he was going in the same direction so she was ok for him to walk with her.
“However, this turned into a terrifying attack and we are determined to find the man responsible.
“We are currently checking CCTV from the area but would appeal to anyone who may have been in the area or who maybe heard a disturbance around that time to contact police.”
Anyone with information is asked to contact Clydebank Police Office on 0141 532 3300 or Crimestoppers on 0800 555 111.
It came as police continued to search for a serial sex attacker who followed and assaulted three women in Glasgow in the space of two weeks.
A 23-year-old woman was attacked on January 24 at 4.20pm in a close of flats in Great Western Road.
In the second incident on January 31 a 19-year-old woman was assualted in a close in Arlington Street shortly before 6.30pm.
And in another attack on February 3 a 20-year-old woman was attacked in a close in Kersland Street at around 5pm.
As we reported last Wednesday, police have been scouring through hundreds of hours of CCTV footage and are currently verifying images after discovering a lead.
Glasgow University has also launched a drive to help their female students stay safe when they are walking home.