This is also trivial info, but you know what I've learned?
I think season 2 of Thomas was originally going to be the final season of Thomas and Friends. Cause think about it. They were practically piling through to the end of Wilbert's stories with a few Christopher ones in between, and then the crew focused on TUGS which didn't last long in 1988. Then Shining Time Station brought Thomas to America in 1989 and it became even more popular, and alas, more seasons came about.
This is why I feel like seasons 3 and 4 were originally made - to continue making episodes for Shining Time Station, and 5 was promoting the new movie. Afterwards, the show just casually continued due to popularity.