Jack is a front-and-loader. He is red with with a cream cab. He also has the number 11 on his cab. He is one of the 12 members of the Sodor Construction Company/Miss Jenny's Pack. Back when he first arrived, he acted like a toddler, always eager to do work, even when the job isn't assigned to him. But after saving Thomas from a collapsing bridge, he changed his ways and became a more responsible vehicle. In The Engines of Sodor, he appeared in The Road Rebel with Rollers where he and Terence worked alongside George, and ignored his typical ranting. His second appearance was in A Breakthrough Discovery, where he, Alfie, and Oliver the Excavator were delivered by Henry to investigate a mysterious sound at an old plant, which turned out to be Jim underground. He is voiced by Thomas1Edward2Henry3 in that episode. His model is from Hilltracks Trainz Routes.