I once had a discussion about this with a coworker…Thomas the Tank Engine has been made in O and G scale by Lionel, HO by Bachmann, and OO by Hornby. But he and some of his friends are also made in N scale by Tomix.
Is a Thomas the Tank Engine set in N scale too small for little children? Thomas is very popular within the toddler age group, and I would assume that being such, larger scales would be a more reasonable platform for Thomas. But I guess it didn’t go too well in G scale, as Lionel stopped making him for it. In O scale, it is only Thomas and Percy. HO seems to be the most popular in Thomas for the USA. OO in Britain. But…Is he most popular in N scale in Japan?
Are adults buying these sets for themselves, or to run for their children/grandchildren? I realize that anything could possibly be true here, but it is digging at my mind for some reason…
Any personal experiences with the purchase of these products for yourself, or for a child, has anyone used the Tomix products, et cetera, et cetera? It just may get it out of my head…[:D]
to run for grandchildren, indoctrinate, inculcate and create an early train addiction, hopefully lifelong. 
Doug, in Utah, Grandpa of Cam, in Utah
I have the N sclae version of this. I would not give it to children. I would give O or HO to children.
I bought the N scale Thomas to run on N-TRAK for the benefit of children. I used to belong to a club that would often set up with a tinplate group. Every time that the tinplaters put Thomas onto the track, we N-TRAKkers lost our audience. The children would all start screaming about Thomas. At that time, the TOMIX was not yet available. I bought a Thomas bubblestuff toy, cut it up and jammed it onto the chassis of an old Atlas 0-6-0T. It kept the children.
The N scale set runs allright; good enough for small children to look at, but not own or operate.
You could try to make Thomas out of the old LifeLike Little Joe 0-6-0 shifter. Get some blue & white paint. Park him on the side of the road. Tell the kids Thomas is resting. Actually, the Little Joe can be a good loco if you take the time to break it in carefully. It tends to stall on turnouts due to the short wheelbase. I don’t have the Tomix version to compare it to, but it may suffer a similar fate.
N scale is for 10yr ols & up. You could always get some English proto equipment to make the cars. They als seem to be in short supply.
Making the two 4-wheel cars for Thomas would be tricky - Graham Farish offered a couple of similar cars many years ago, but getting hold of them now is a case of “buy when you can” through ebay or sometimes LHS used sections. I’ve seen very few of them. Thomas himself could possibly be modelled from the old GraFar “General Purpose” tank loco but the running qualities of their older locos are rather less than most people will accept (I used to have a fleet of six, now only one still runs properly).