A/N I believe Thomas's illness was near his brakes, like something in his wheels, perhaps axles or something.
Hey, it's me, Thomas again. This time I shall tell about when I was a runaway. It happened because I was ill, affected in the area near my brakes.
I was ill. Workmen had tried hard to make me better but it was no use. My illness could be fixed only at the Works.
"Edward must take you to the Works," said Sir Topham Hatt.
I felt very miserable. My friend Edward did what he could to comfort me and then we were off. Then, Sir Topham Hatt spoke to Duck.
"I want you to help Percy and Toby while Thomas is away." I heard him as I was leaving. Duck being another tank engine combined with his work at the time was probably why he replaced me for the time I was away. I found out how Duck did while I was at the Works when I came back.
Duck was delighted. He already knew Percy and soon made friends with Toby and Bertie. Terence the Tractor gave him a big welcome.
"Take care of Thomas's coaches, he advised. "He's sure to miss them while he's away.". Terence knew how I can get about Annie and Clarabel, as in it would make me very unhappy if something happened to them. I feel quite deeply.
Duck was very gentle with the coaches. Annie and Clarabel were impressed.
"Such nice manners," they told each other. "It really is a pleasure to go out with him.".
When I came back from the Works, Annie and Clarabel told me how well Duck had managed. I was so pleased to be home I forgot to be jealous. The Works had left my handbrakes very stiff. It made my brakes seem they were on. when in fact they were not. As a result, my coaches and I often overran the platform. I found this most embarrassing. Gradually, Driver and my fireman learned to be extra careful. But one day, my fireman was ill and a relief man took his place. The fireman had fastened the coupling and joined the driver and stationmaster on the platform to wait for Henry's passengers. The fireman had forgot all about my handbrake. I simmered happily.
Not long now, I thought as I saw Henry slowly approaching. But my brakes were not on and suddenly I felt my wheels begin to move. I tried to stop, but I couldn't without Driver and my fireman. I tried to whistle a warning, but I couldn't do that either. The conductor, Driver, fireman and passengers were all stranded on the platform. I might be alive, but I didn't know how to apply my brakes or whistle without my crew there.
"Stop! Stop!" shrieked Annie and Clarabel.
But, I, with plenty of steam, kept on going. The alarm went down the line.
"Stop the runaway!" That was the signalman, referring to me.
There, ready for action was Harold the Helicopter. The inspector had made a plan and together they took off into the sky. At last Thomas was tiring.
"I need to stop, I need to stop," I panted wearily. As we neared the next station, I saw Harold land. Soon, I would learn of their plan, the people in Harold. They entered the platform slowly enough for the inspector to act. Judging his moment, the inspector scrambled into the cab and screwed the brakes on.
At last, I stopped. Both the inspector and I were very relieved. Then, we thanked Harold.
"Think nothing of it. Glad to be of service anytime." That's what that Harold Helicopter said to us.
"Thomas," remarked the inspector. "We must never let this happen again."
Wearily, I agreed with him. After that, my brakes were made less stiff by workmen so it never would happen.
A/N For the last line, imagine what you need to make it make sense, as far as him going to the Works or not.