Stephen is an old steam engine, who is nicknamed the Rocket.
Stephen was an old engine who had been brought to the Railway by the Earl. After a long duration of repairs at the Crovan's Gate Works, he became trapped in a mine trying to be useful. Spending the night on the lonely dark mine, Stephen inadvertantly uncovered King Godred's lost crown! After the Earl, Thomas, James, Percy and Jack rescued him, he was taken to Ulfstead Castle in fine fashion. Nowadays, Stephen acts as a "tour guide" at Ulfstead Castle.