Still building steam at 60.
This year Thomas the Tank Engine is old enough to get a bus pass. Rhodri Clark reports.
It's remarkable that Thomas and his friends still have such a powerful grip on children's imagination, 60 years after they first appeared in print.
Steam engines have long since disappeared from everyday use, but children still identify with Thomas, Percy, Gordon and James.
Many of today's children are ferried around in cars and rarely or never go anywhere by train, but they're still as interested in Annie and Clarabel (Thomas's coaches) as children were in the 1950s.
Wilbert Awdry, an English rector, began telling stories about railway engines when his son Christopher was ill with measles in 1943.
Much of the detail was elicited by Christopher in a series of questions, to which his father had to reply nimbly.
Christopher wanted the stories again and again and would have been quick to point out any inconsistencies. So Wilbert wrote them down to ensure consistency.
His wife, Margaret, encouraged him to send the stories to publishers but all the big companies rejected the manuscripts. Eventually, in September 1943, an obscure printer in Leicester called Edmund Ward agreed to publish the stories for a fee of pounds 25. Paper shortages delayed publication, but the first copies became available in 1945, while Britain was still euphoric after the end of the Second World War in Europe.
Thomas the Tank Engine did not feature in the first book, which concerned three other engines. But Christopher's present for Christmas 1945 was a blue wooden tank engine (so called because the water is carried in tanks on the engine, rather than in a separate tender truck) constructed by his father.
The youngster named the new engine Thomas, and in 1946 Thomas the Tank Engine made his debut in the second volume.
The books were such a success that Awdry wrote a new one each year for 26 years.
Diesel trains rapidly replaced steam in that period, to the dismay of rail enthusiasts like Wilbert Awdry, and the diesels in his stories are often pretty unpleasant characters or, in the case of Daisy, too delicate to be much use.
This was also the era of the Beeching cuts, where buses replaced many branch-line trains. Buses also get a fairly bad press in the stories.
In 1961 the two-millionth book in the series was sold. Each book had several endearing features, besides the characters themselves. The format was small enough for little hands to hold easily and every right-hand page was devoted to a colour illustration ( features shared with the Beatrix Potter stories. Each volume contained several stories which could stand alone or be read in sequence.
The stories ( which are now published by Egmont ( were written in simple, direct language and could convey fairly complex situations in a few brief pages.
"There are probably as many reasons for their success as people reading the books," says Christopher Awdry. He recalls little of the early days except that he was feted by his peers in school for a few days because of his father's achievement, then forgotten.
He adds: "Parents like the books because they're educative ( kids learn numbers, colours and how to read. Autistic children seem to cotton on in quite a big way. The stories are easy to read out loud to small children, and the children can identify with the characters."
Many of today's children know about Thomas and friends not through the books but through the television series and associated merchandise. Thomas the Tank Engine and Friends has become an international brand on a par with anything from Disney.
This marketing phenomenon was presaged back in the 1960s, when the Meccano company produced a Percy train set and broadcaster Johnny Morris, presenter of the TV programme Animal Magic, narrated and supplied the steam-train noises for a series of vinyl records.
Before that, in 1953, the BBC had attempted to animate the stories using adapted Hornby Dublo model trains. But the show went out live and after a few derailments and other problems the plug was hastily pulled.
The press was delighted, the Daily Mail featuring the fiasco on its front page.
The first properly made films, with narrative by Ringo Starr, were aired in 1984 after a children's television producer called Britt Allcroft negotiated TV rights. Within months, the ITV broadcasts were attracting 8.5m viewers.
Thomas hit US television screens in 1989 and chugged into Japan in 1991 and Germany in 1997. He now entertains in 130 countries.
Thomas made it on to the big screen in 2000, with the release of the feature film Thomas and the Magic Railroad. The use of the American word for railway betrays an attempt to make the film a hit in US cinemas. Box office receipts topped pounds 2m.
The original films, later narrated by Michael Angelis, closely followed Wilbert Awdry's tales, but in recent years the concept has been expanded with the addition of numerous new characters.
Before his death in 1997, Wilbert expressed concern that the care he took to keep the stories authentic, save for the engines' faces, was being abandoned.
Christopher, who in 1983 started writing further books in the railway series, is also unimpressed.
But Christopher Awdry says the films have encouraged many children to read the books. Thomas has served him exceptionally well. He gave up his job with the Inland Revenue and now travels around Britain to read to children and sign books.
The toy trade also benefits. And that's before you add in the duvet covers, wallpaper, party gear, lunch boxes and other goods branded with Thomas's familiar smile.
With so much Thomas gear available, it is easy to forget that the stories are part of the remarkable body of ground-breaking children's literature from Britain in the 20th Century. And despite their inauspicious start, they still bear comparison with modern fiction for young children.