Plot hole: James appears in every episode before his introduction in "Thomas and the Breakdown Train." Also, James is supposed to be black, because at the end of the episode, James is told he will get a different coat of paint. (He is also black in the book).
Plot hole: How could Gordon's driver tell the station master that Gordon couldn't get up the hill? There are no phones on Gordon's hill.
Answer: Breakdown trains help the engines back on track.