Jack and Alfie Swap is a cancelled episode of Jack and the Sodor Construction Company.
On a demolition site, everyone is extremely busy, except for Alfie, who spends all day digging. He is jealous and asks if he can swap jobs with Jack who spends the day flitting about on the site. The next day Jack spends the day continuously digging and Alfie, now doing Jack's job, clatters from one side of the site to the other all day long. He gets exhausted.
Jack enjoys his break but becomes restless. That night, Jack asks Alfie if they can switch back, but exhausted Alfie is already asleep.