Police are hoping to use artist's impressions to identify some of the unclaimed bodies found on Britain's rail network in the last 35 years.
Artist Sharon McDonagh has drawn pictures of 20 of the deceased.
None of them is believed to have been the victim of foul play and most were hit by trains.
Detective Chief Superintendent Miles Flood said: "It is likely there are still relatives who may recognise them and thought they had moved away."
The images are being released by the British Transport Police and the National Police Improvement Agency (NPIA) in a unique attempt to close the files on fatalities stretching back to 1975.
Anyone with any information about these people is asked to call British Transport Police on 0121 634 5613 quoting the drawing reference number.
Most of the 20 images relate to people whose bodies were found in the London area - although they may have come from anywhere in the country - while one was found in Coventry and another one in Cornwall.
About 200 to 300 people are killed on the UK's railways every year.
In total, there have been 44 unidentified bodies - out of 9,000 deaths - found on railway lines in England, Scotland and Wales in recent decades.
Mr Flood, from British Transport Police, said: "All these fatalities were fully investigated at the time and all clues followed up to try to establish an identity, but without success.
"We are now taking another look to see if there is any more we can do, in some cases to see if advances in forensic techniques can help, and to appeal to the public to see if anyone recognises them."
"Some of these people may have had an itinerant lifestyle but it is likely that there are still relatives or friends who may recognise them and thought they had simply moved away."
It is the first of a number of reviews being conducted by the NPIA in an attempt to identify hundreds of unidentified bodies in police files across the country.
Their next initiative will work with police officers in Kent, Sussex and Hampshire - where many of the unidentified bodies were found at sea.
There are 44,000 people listed on the UK's Missing Persons' Bureau database.
The NPIA, which was told last month it was being scrapped by the government as part of its savings programme, maintains a database of unidentified bodies.
It is also providing funding and operational support so forces can conduct cold case reviews to identify these mystery people.
Chief Constable Peter Neyroud, the NPIA's chief executive, said: "The NPIA is the centre of expertise for the police service in cases of missing people.
"There are around 1,000 cases of unidentified bodies across the country, dating back more than 50 years.
"We are trying to create stories with endings for families who may still be grieving.
"It is extraordinary how many people know someone who has gone missing. Most of them return but many do not and these stories have no endings."
'Feel for person'
Police believe some of the 1,000 cases may turn out to have been murders, while others will inevitably be foreigners.
One missing person, identified earlier this year, was Ian Allison - a missing person who was last seen in 1994, when he was believed to have been hitchhiking from Torquay to Glasgow.
A body was found in Cumbria in 1995 but it was not identified as Mr Allison until earlier this year.
On Wednesday his mother, Mary Allison, from Glasgow, went to Cumbria to pick out a headstone for his grave.
Another recently identified body was that of Lesley Ann Pickavance, from Bedford, who died after being hit by several cars on the M25 in Hertfordshire in July 1990.
Facial imaging specialist Sharon McDonagh, from Leeds, is one of a handful of accredited police artists.
She said: "What I try to do is to recreate what the person would have looked like alive, to breathe life back into them, if you like."
It was grim work. Her only source material was a mortuary photograph.
She said: "Although I only have a picture of a face to work from, I use all the information about that person.
"If you know they are of slim build for instance that will affect the way you draw their face; if you know something about their background, you can get a feel for the person."