What is the rarest Thomas and friend train?

The rarest Thomas and Friends train is often considered to be the "Golden Thomas," a limited edition version released for the show's 60th anniversary. Another highly sought-after item is the "Thomas the Tank Engine prototype," which is unique and not available to the public. Collectors also prize other limited releases and promotional items that were produced in very small quantities. The value of these rare trains can reach thousands of dollars among enthusiasts.