Families are being urged to step out on a sponsored train walk at Avon Valley Railway in Bitton.

The event has been organised by the South Gloucestershire branch of the National Autistic Society (NAS) to raise money for its work.

Based on the classic Thomas the Tank Engine books and characters, the ramble will involve local families and friends walking together in a long train.

They will be sent on their way by Councillor Shirley Holloway, the recently elected chairwoman of South Gloucestershire Council.

Children will also be able to get their faces painted and see some small zoo animals at close quarters.

Everyone taking part in the event on Sunday, June 14, will be given a free steam train ride from the station.

Rachel Trueman, NAS South Gloucestershire branch officer, said all the money raised would go towards providing services to local people.

She said: "Autism is a serious, lifelong and disabling condition, but the right support – at the right time – can make an enormous difference to people's lives.

"We hope to see as many people as possible having fun and raising vital funds for our branch."

Autism is a disability that affects more than 500,000 people in the UK and anyone who wants to join the Bitton walk should telephone Rachel on 07917 085132.