Percy is a green saddletank engine.
Season 1 - Races, Paxton Helps Out, Where's BoCo?, Bulgy the Vegetable Bus (cameo), The New Diesel Fuel (cameo), Repairing Old Slow Coach, Bears, Thomas and the Kitten, Oliver and the Snowstorm (cameo), Dave the Diesel (cameo), Salty Fries (cameo), Bothered Byron, Donald, Douglas and the Fallen Tree (does not speak), and The Lightning Tree
Season 2 - Hay, The Magic Railroad, Tim and Tom, Daisy and the Chickens, Sodor Blackout, Down by the Docks, Hiro goes Home, Kelly's Stormy Day (does not speak), Off to the Scrapyards, Thomas and the Christmas Surprise (cameo), and Percy and the Other Railway
Season 3 - Apples (does not speak), Red Paint, Grumpy George, Replacing the Logging Locos, The Mail Depot, Harvey Joins the Team, Sir Handel, Rusty and the Runaway Boulder, Oliver and the Old Mansion (does not speak), Musical Whistles, Snowmen, and Duke Returns
Season 4 - Peter Sam's Delivery, Diesel and the Barge, The Return of D199, Fishy Trouble (does not speak), The Trouble with Trucks, Tiger Moth the Show-off, Stanley and the Old Scrap, Buster and George, James the Really Splendid Engine and Percy and the Scottish Castle