Thomas, which says that the show uses specially modified Märklin O-scale
locos, and since this has been disputed, I went ahead and asked the
proverbial horse's mouth. I just received an email reply to my question
to them, in which they say:
Thank you for contacting us. The actual engine size used is a
> standard O Gauge. Unfortunately, this is all the information we have to share. >
> Thank you for your interest in Thomas the Tank Engine.
>
> Kris HIT Entertainment Consumer Relations
(I'm assuming here that "O gauge" == "O scale".)> standard O Gauge. Unfortunately, this is all the information we have to share. >
> Thank you for your interest in Thomas the Tank Engine.
>
> Kris HIT Entertainment Consumer Relations
So I guess for those who say it ain't so, my answer is to take it up
with them. (The show is owned by HIT Entertainment, and I reached them
at snipped-for-privacy@hitentertainment.com.