Suggestions by @jdfitzgerald

Alan Marriott

as Trevor in Thomas storybook episodes

Michael Caine

as Toby in Thomas' Sodor Kringle Christmas and the Magic Railroad

Lacey Chabert

as Emily in Thomas' Sodor Kringle Christmas and the Magic Railroad

Emma Watson

as Mavis in Thomas' Sodor Kringle Christmas and the Magic Railroad

Hugh Jackman

as Henry in Thomas' Sodor Kringle Christmas and the Magic Railroad

Ewan McGregor

as Edward in Thomas' Sodor Kringle Christmas and the Magic Railroad

Simon Pegg

as Bertie in Thomas' Sodor Kringle Christmas and the Magic Railroad

Richard Osman

as Harold in Thomas' Sodor Kringle Christmas and the Magic Railroad

Richard Hammond

as Oliver the little western in Thomas and the Magic Railroad

Steven Kynman

as Duck in Thomas The Tank Engine (A Marc Forster Film)

Robert Downey Jr.

as Victor in Thomas & Friends

Adam Howden

as Billy in Thomas & Friends

Sally Hawkins

as Henrietta in Thomas & Friends

Julie Walters

as Old slow coach in Thomas & Friends

Chris and Liam Hemsworth

as Mighty Mac in Thomas & Friends

Bob Golding

as Freddie in Thomas & Friends

Sam Neill

as Jeremy in Thomas & Friends

Eddie Izzard

as Arthur in Thomas & Friends

Ewan McGregor

as Edward in Thomas & Friends

Alan Cumming

as Duncan in Thomas & Friends