Mr. Peregrine Percival (also called "the Thin Controller") is the manager of the Skarloey Railway in the television series. He was hired sometime between the events of the seventh and ninth season to help the Fat Controller manage the ever-increasing size of his railway industry.
According to a bio from a "Thomas and Friends" magazine, he has had four children with his wife, Polly Percival. He also hates cars, which explains his signature bicycle. It is also revealed his hero is Sir Topham Hatt.