Gordon is a blue big tender engine.
Season 1 - Races. Paxton Helps Out, The New Diesel Fuel (cameo), Repairing Old Slow Coach (cameo), Bears, Whiff the Clean Engine (cameo), Dave the Diesel (cameo), Salty Fries, James and the Ice Cream, and Dash and the Fair
Season 2 - Unique Stafford, The Magic Railroad, Tim and Tom (cameo), Daisy and the Chickens (cameo), Sodor Blackout (cameo), Down by the Docks (cameo), The Bees' Knees (cameo), Hiro goes Home, Off to the Scrapyards, and Thomas and the Christmas Surprise (cameo)
Season 3 - Murdoch and the Heavy Goods Train, Apples (does not speak), Red Paint, Grumpy George, and Replacing the Logging Locos, The Tug (cameo), Scruff's Dirty Job, Out of the Mine, Oliver and the Old Mansion, Musical Whistles, Snowmen, and Duke Returns
He is likely to appear in Season 6