The Polar Express Wiki

Wikipedia has an article related to:

Daryl Christopher Sabara (born June 14, 1992) is an American actor, perhaps best known for playing Juni Cortez in the Spy Kids film series. He also did the voice of Hero Boy in The Polar Express film and video game. For the role, he mimicked the voice of Tom Hanks[1], who did Hero Boy's motion capture and adult voice.

His twin brother, Evan also worked on the film, doing additional motion capture for Young Boy.