Lexi is a boisterous cab-forward experimental engine. Lexi likes to experiment with how she presents herself, often trying out different voices and how she phrases her expressions just to see which one she thinks works best. Another “experimental engine”, she is “cab forward”, even though she is convinced this this makes her “an un-useful engine."
When Thomas travelled to the Mainland, he befriended the experimental engines: Lexi, Theo, and Merlin. Thomas encountered Lexi and Theo in an empty yard, where he was warmly welcomed and refilled with coal. Later, Lexi, along with the other experimentals, helped Thomas rescue James, who had been trapped in the Steelworks.
Afterwards, Thomas encouraged Lexi (along with Theo and Merlin) to stay with Frankie and Hurricane and call the Steelworks their new home.
- She will meet Pooh, Littlefoot, Simba, Sora, Mickey, SpongeBob, Tai, Twilight Sparkle and their friends in Pooh's Adventures of Thomas & Friends: Journey Beyond Sodor.