Bassett the Small Museum Engine

Bassett is a cheerful little engine who lives in the Arlesdale Railway's museum. He started life as an unfinished project, then when he was completed went on to work in an amusement park and holiday camp. When his work ceased, he was donated to the Arlesdale Railway, where they fully restored him and put him on display. Every now and then he'll come out and help the other engines, but can't do too much because of his size and strength.

You can read about him in the Sodor Island Forum's ERS Library, in the following books:
ERS 93- The Small Railway Gala
ERS 146- The Arlesdale Engines