A/N Henry the Green Engine before Gordon arrived on Sodor and right at his arrival, too..
Henry found out the new Express coaches were too heavy for Edward, the old Express engine to pull after he began his work on the Northwestern Railway. He was finicky due to his design, but when they didn't have poor coal, he was strong. Sometimes, he pulled heavy freight, too.
One day, Henry had a stuffy firebox. He was unable to make steam properly, so his crew cleaned him out. Then, he took a mile-long freight train to the Mainland. He came back over the Sodor bridge and whistled when he came back to Vicarstown. This is my home, now, he thought. Some of the engines borrowed from the Mainland were mean to Henry, but his driver was there for him, drying his tears. Sir Topham Hatt was told and the mean pair were sent back to their home railway, as one was a passenger engine and one was a freight engine. Since Henry was a mixed-traffic engine, those other engines were needed so little they were pointless to keep. However, Henry's tendency to run out of steam meant other engines were needed.
A smaller engine, no bigger than Edward, but black was on trial on Sodor. His name was James and, like Edward and Henry, he was a mixed-traffic engine. Henry, even if he could be vain or grumpy, wished James well and hoped the smaller engine would be an NWR engine.
Due to Henry being a poor steamer, an engine from Doncaster was brought in. Gordon became the Express engine. Because of being big engines, they hung together. Gordon had been cured of defects he had, as an experimental prototype of his class, unlike Henry. Henry's builder hadn't known Henry was experimental until he was built. Gordon was bought because Henry ran out of steam sometimes, due to his design flaws. Though Henry was used on heavy freight trains, because the other engines left on Sodor were passenger engines or else too small for heavy freight.
A/N I had some steam issues with this chapter and due to my difficulty in working up steam, I threw in a fan theory about James appearing before his first official day meaning he was on trial.