Sophie George: Parents convicted of manslaughter

They were laying on the track dropping stones into the river below near Borth, close to Aberystwyth.

Reverend Liam Johnson of the Railway Mission led the prayer service before unveiling the memorial.

"I felt it was important to have a memorial because of the unique circumstances of the tragedy," he said.

"These two girls lost their lives in very upsetting circumstances and it is important to remember that.

"The memorial is on a pathway one mile from the bridge where the accident happened on the outskirts of the village of Tre'r-ddol where they lived.

"It will also help remind people that despite the peaceful surroundings, railways are dangerous places and you should not go on them."

Kymberly Allcock died in the tragedy

This summer Sophie's mother and stepfather, Amanda and Gareth Edwards, were found guilty of manslaughter after allowing the children to play on the railway during a picnic.

They were given a 12-month prison sentence, suspended for 12 months, in a court case in Swansea.

A prosecution against Railtrack and the Countryside Council for Wales for alleged breaches of Health and Safety rules, which came to light as a result of the tragedy, is expected to go ahead next year.

The organisations have both denied allegations of health and safety breaches.