A bit pedantic. If he was watching trains at Box why is Thomas remarkably similar to a LBSC E2 0-6-0T.
As for James has anyone worked out the prototype? Wikipedia gives:
James the Red Engine is a mixed-traffic L&YR Class 28 'Mogul' 2-6-0 tender engine. But the 28s were 0-6-0s.
It was the artist who illustrated the Railway Series books who drew Thomas as an E2 0-6-0T. The author only gives a very general description of him in the text.
According to the book 'The Island of Sodor, Its people, history and railways' by The Rev W. Awdry and G. Awdry' (and they ought to know), James is a L&YR Class 28 0-6-0, but as this class 'had a tendency to be nose-heavy especially when...driven at speed the designer George Hughes, in an effort to counteract this defect, built the engine we now know as James with 5' 6" coupled wheels, and a pony truck in front. The design did not entirely produce the improvement hoped for, and after the Grouping the
LMS▸ sold this engine to the North Western Railway [i.e. the main line railway of Sodor] who have now corrected most of the faults in the design, including the wooden brake blocks'.