The TV Thomas industry was born out of Britt Allcroft's intents of becoming a millionaire rather than what Awdry wished. Awdry hated the fact Britt was cashing Thomas out and subsequently taking the TV series it's own direction. The departure began around 1992 with the third season of the TV show.If anything, I think that the "Thomas industry" and all that is associated with it, does railway modelling more harm than good.
However, the directors didn't take his complaints seriously. By the fifth season (1998), the show had completely departed from Awdry's stories with no real resemblance to the original Railway Series books. A few episodes were based on real incidents, but nothing from Awdry's books. Many episodes were miserably unrealistic as well."Merely reveal their lamentable ignorance of railway matters! That such rubbish should be credited to me is a gross insult!"
Allcroft kept her monopoly on Thomas until her big budget film (Thomas and the Magic Railroad) was a massive box office flop, which resulted in her being ousted from top tier in her own production company. I cannot comment much on HiT's work with Thomas, but I feel they missed an opportunity by not going back to the "original" Thomas and adapting the remaining Railway Series books. It seems, though, the TV Thomas series now mostly exists for the sake of toy sales rather than what it began as (decent Railway Series adaptions for TV).
The Railway Series, on the other hand, never really cashed itself out badly, merchandise being restricted to "bare essentials" (books, some models, some other books, few other goods) and the series never gave into massive hype as the TV show did. The last RWS book was published last year. Realism was always a key in the RWS books, this I think would have helped children become interested in real railways and how they worked.
On another note, look at this old news article about Britt Allcroft and one of Awdry's sources of influence.
http://news.bbc.co.uk/2/hi/uk_news/wales/619832.stm
