Harold


 * ''If looking for the ancient Sudrian king, see Harold (King of Sodor).

Harold is a helicopter used for patrolling the railway. When he first met Percy, he stated that railways were "slow and out-of-date", but was proven wrong when Percy later beat him in a race.

In the television series, he first appeared in the second season. In the Railway Series, he first appeared in "Percy the Small Engine", and later reappeared in "More About Thomas the Tank Engine" and "Thomas Comes Home". He also appeared in the non-Railway Series book "Thomas and the Missing Christmas Tree to take Father Christmas to the Christmas party.