The simple stories and clear facial expressions of the Thomas the Tank Engine characters have made them a favourite among children with autism, according to a study by the U.K. National Autistic Society.

Thomas the Tank Engine, written in 1943 by Rev. Wilbert Vere Awdry, is a perennial favourite among all the under-four set, especially for boys who love trains.

Thomas the Tank Engine, in a 1998 promotional photo for Thomas & Friends. His easy-to-read expressions appeal to autistic children.
(Canadian Press)

But it appears to have particular appeal to autistic children, with 58 per cent of parents in an April 2007 survey reporting that Thomas was the first children's character their child enjoyed.

Most of the children discovered Thomas & Friends through the television show based on the characters, but then moved on to Thomas toys, videos and books.

Among autistic children, who often have a narrow range of behaviours, Thomas-related play was often their favourite activity, with children repeatedly watching the videos and reenacting whole scenes, including dialogue, with the toys.

"Thomas & Friends is 100 per cent responsible for getting him talking. Thomas was his life," said one parent of a nine-year-old, according to the NAS survey.

About a third of parents reported their children were able to learn basic facial expressions from the characters, as all of Thomas's friends have easy-to-read expressions — they are either happy, sad or angry.

Children with autism often have trouble decoding human expressions.

"He definitely uses the train faces to distinguish between different emotions. Thomas has helped him to get into the world of not just language but also how people feel," said another parent.

Parents also believed the characters contributed to their children's learning of colours, numbers and language.

The gentle world of Thomas & Friends, in which characters behave predictably, helped to calm some autistic children, with 54 per cent of parents reporting the stories contributed to their child's sense of security.

Children with autism enjoyed the Thomas stories and characters up to two years longer than siblings who didn't have the disorder.

The survey was answered by 748 U.K. parents of children under 10 with autism, a developmental disability.

Thomas the Tank Engine stories have been voiced by Ringo Starr and George Carlin and a new version of the TV series will feature the voice of Pierce Brosnan.