Mighty Mac is a double-sided Double Fairlie.
When Mighty Mac first arrived, they were unexpirienced as they had only worked at shunting yards. They began to disagree on which way to go, and ended up trapping themselfs at a dead end. However, they managed to break through the rocks, and get their passengers to their destination.
Mighty Mac is painted royal blue with yellow and red lining. On Mighty's side, his cab windows and tank caps are lined with yellow, while on Mac's side, they're lined with red.
- Season 2 - Paul and Rusty and The Importance of Being Neville
- Season 3 - Paul and the Weedkiller and Luke and the Christmas Party
- Season 4 - Duncan and Victor
- Season 5 - High Expectations and Creepy Cutting
The Adventures on Sodor
- Season 1 - Old and Wise (cameo), Skarloey Comes Home, Rheneas' Risky Ride, Gordon, Spencer and the Flying Scotsman (Mighty speaks; Mac does not speak), and Rusty Rescue (cameo)
- Season 2 - Trouble on the Line (cameo), The Return of Boulder (cameo), Duncan's Discovery (Mighty speaks; Mac does not speak), and The "Ghost" Warrior (cameo)
- The Great Storm of Sodor (do not speak)
The Many Adventures on the Island of Sodor
- Season 1 - Luke's Lucky Find (cameo), Old Engine, New Changes (cameo), and Duke Does it Again
- Season 2 - Clean vs. Dirty (cameo), Peter Sam and the Lost Engine (cameo), and The Search for Neil (cameo)