>>7911000>>7911195>>7911232>>7911970>>7912306>>7912333>>7912349>>7912358RWS autist here. A small difference comparing the early episodes to the books is that each book usually has a light overarching narrative focusing on one character. The adapted episodes were shuffled out of order, which loses some aspects of character development.
For example, the book Gordon the big Engine starts with Off the Rails. He is a stubborn asshole and derails himself rather than take a goods train. This was adapted in S1.
In the next story, Leaves, (this was adapted into the Trouble with Mud, season 3), Gordon has been delegated to goods work as punishment. He helps James up the hill and atones a little for his bad behaviour.
The next story, Down the Mine, he helps Thomas (who disgraces himself) and they form an alliance to help each other. Again adapted in S1.
The final story, Paint Pots and Queens (S4) the allied Gordon and Thomas each ask the Fat Controller to forgive the other. Gordon gets into TFC's good graces and gets to pull the Royal Train.
Note that whilst he is still boastful, never again in the books does Gordon do something as stupid as derail himself to avoid pulling trucks.
In the TV series, these episodes are all over the place, losing the overall arc of Gordon's punishment/redemption. The first series is the only series where the stories are adapted from the books more or less in order, and it's the only one where you can feel these little arcs coming into play.