Thomas is the No. 1 blue engine. He is a cheeky little engine who often gets into scrapes, usually by being over-eager to do things best left to bigger and more sensible engines. But clouds never last long in Thomas' world and soon he's bustling about again, playing his part in the yard and on his very own branch line. Thomas works hard and he always strives to be a Really Useful Engine.
Thomas is based on the London Brighton and South Coast Railway 0-6-0 E2 with extended side tanks.