Two people died in one day last month after falling 150ft (46m) from the structure at Redruth onto a road below.

The Samaritans say they hope the signs will make people stop and think before taking such action.

Network Rail said it was among a number of initiatives being introduced to try and stop people.

We've got one thing that a lot of people haven't got in this day and age - and that's time Duncan, The Samaritans

The viaduct towers above one of the main roads through the town centre which is flanked by shops, offices and homes.

Mike Underwood, who runs a fishing shop immediately below the bridge, witnessed one recent incident.

He said: "This guy jumped off. I covered him up, and people did what they could. Police and an ambulance arrived and he was moved after a couple of hours.

"But something ought to be done because it seems like it's easy to get on the railway. It's very distressing."

The charity is meeting the cost of the measures.

Duncan, the charity's Cornwall director, said he was aware the signs will not stop everyone, but he said if they made one person stop they would have served their purpose.

Series of measures

Duncan said: "We've got one thing that a lot of people haven't got in this day and age - and that's time.

"You can talk to us, no matter how long it takes. We hope people will notice our number and ring."

Network Rail Maintenance manager Rob Mashford said the signs were the first in a series of measures.

He said: "There is already fencing in the area to stop people just walking off the platform. But we're looking at upgrading that and putting in trespass guards, which are like cattle grids which go across the rail lines and make it more difficult to get there.

"We're also looking at upgrading CCTV already at the station so staff can see people walking down the platform."

The Samaritans is also hopeful it will get permission to put signs near a bridge on the A30 dual carriageway near the town, where there have been similar incidents.