Continuity mistake: When the Iron Giant follows Hogarth home they cross a railwayline and the Giant starts to eat the steel rail. During this scene you can see the distance of the railway sleepers changing from a fair distance apart to close together over the course of the shots. In the same scene you can also see that, although there is a crossing with lights, no vehicle could possibly pass as the rail has no crossover facility at that level. (00:24:30)

The Iron Giant (1999)
Plot summary
Directed by: Brad Bird
Starring: Jennifer Aniston, Vin Diesel, Harry Connick Jr., James Gammon
Hogarth Hughes is a 9-year-old boy living in Rockwell, Maine in 1957. One night, while home alone, a large object comes crashing down from the sky and lands behind his house. He goes to investigate, and comes across a robotic giant feeding on the metal in a power plant. Hogarth is chased away by the strange machine, but returns and meets up with him again the next morning. The giant begins to follow him home, and Hogarth eventually allows him to live in the shed behind his house. Hogarth befriends the giant and the giant begins to speak and even learn. However, Kent Mansley, a government agent, sees the giant as a threat to the country, and isn't about to let him get away...
Dean McCoppin: Oh, hey, I know you. Squirrel boy.
Hogarth Hughes: Uh, Hogarth.
Dean McCoppin: By night known as Hogarth.





Answer: Turn back to/from what? Can you please expand on the question so we know what you're referring to?