Theo is a Shy Experimental Railway Traction Engine. He is Good friends with Merlin and Lexi and works with Them. He is a Brown, Dark Green and Red Experimental Steam Engine with a Very Big Wheel in The Middle.
Appearances: Season 16: episode 238
He Will Appear in Season 16. Theo Jumps In: One afternoon Fergus' boiler was aching so he decided to take a nap. Later sir topham hatt had a job for him, but Fergus wouldn't wake up so sir topham hatt started sending a traction engine matching his basis. That day the new engine arrived his name was Theo. sir topham hatt gave him instructions about the sodor railway, No Showing off, No horse playing, and no grumbling. Then Theo saw some trucks near Knapford station he decided to move them Edward shouted stop but Theo didn't stop. Then there was trouble Theo chuffed up a hill and he thundered down the hill very fast and came off the rails. Later sir topham hatt arrived he was very cross with him Theo was sad sir topham hatt thought if Theo could do better tommorow, Rocky tried to cheer him up, That made Theo just bit better.