The helicopter patrols will direct police officers to trespassers

Operation Hawk will see helicopter patrols flying over railway lines in mid Wales from Shrewsbury to Machynlleth.

They include a section of the track at Borth near Aberystwyth where Sophie George, seven, and her friend Kymberley Allcock, who was eight, died three years ago after being struck by a train.

British Transport Police and Network Rail are jointly running the helicopter patrols campaign.

The helicopter will spot trespassers on the tracks in an area where people regularly illegally walk over the train lines, often heading towards the coast.

The helicopter launches on Saturday and will operate throughout the summer.

On board will be a transport police officer who will spot trespassers and direct a patrol car to them.

There are a lot of people going to the coast and it's a temptation to cross the lines Network Rail spokeswoman

The scheme has been running in other parts of the country for three years.

It is now being launched in Wales after British Transport Police expanded their operations within the Network Rail area as far north as Bangor.

Inspector Ian MacDonald is one of six air observers working for the scheme.

He said: "It's been very effective in preventing trespassing.

"When we do a lot of press coverage, we find trespassing and vandalism offences tend to drop once they realise the helicopter's going to be in the air.

"What we do is fly in the hotspot areas and if we see anything, we'd call up the ground troops."

The procedure also worked in reverse on occasions, with land vehicles directing the helicopter to sites where offences may be being committed.

The girls who died were playing on the railway line

Detection rates had risen with the use of the helicopter, he added.

A spokeswoman for Network Rail said trespass was a particular issue during the summer.

"[The helicopter] is a very useful way of tackling the problem.

"There are a lot of people going to the coast and it's a temptation to cross the lines," she said.

Sophie and Kymberley, from Tre'rddol near Aberystwyth, were hit by a commuter train in July 2000 while they were lying on the tracks dropping stones into a river below during a family picnic.

Sophie's mother and step-father, Amanda and Gareth Edwards, were later sentenced to a 12-month suspended sentence for manslaughter through gross negligence.