Clarence Reginald Dalby
Dalby illustrated The Railway Series books from the original title, The Three Railway Engines (which he re-illustrated, replacing the original art work by William Middleton), up until Percy the Small Engine.
Although Dalby's illustrations didn't entirely satisfy the author, and errors in detail caused all kinds of problems, his pictures—with their bold lines, lively energy and bright, gem-like colours—quickly caught the imagination of young readers and he undoubtedly set the style for the series.
(Brian Sibley, Thomas the Tank Engine: The Complete Collection)
In the end, the fractious relationship between Dalby and Awdry resulted in Dalby's resignation as illustrator of the series in 1956, following an argument over the portrayal of Percy the Small Engine in the book of the same name. Awdry had written to Dalby, "I beg, pray and exhort you not to make Percy look like a green caterpillar with red stripes!"
He was replaced by John T. Kenney as illustrator.
Dalby, a Leicester man, was also the creator of the original trademark polar bear on Fox's Glacier Mints. Fox's was a firm based in Leicester, which was also home to the Railway Series publishers Edmund Ward.
Dalby died in 1983, aged 79, following a short illness.