Emily is a beautiful girl and the mysterious Emerald stiring single tender engine in Thomas the Tank Engine and Friends.
- Home: Island of Sodor
- Train Built: Steamie
- Appearance: Green tender engine with 4 small wheels at the front, 2 drive wheels in the middle, 2 small wheels behind, and tender with 6 wheels, black smokebox, red chassis, black buffers, grey face, yellow portholes and white lamp
- Numbers: 12
- Gender: Female
- Affiliations: Good
- Allies: Thomas the Tank Engine (boyfriend/husband), Edward the Blue Engine (father), Henry the Green Engine, Gordon the Big Engine, James the Red Engine, Percy the Small Engine (cute friend), Toby the Tram Engine, Duck the Great Western Engine, Donald and Douglas the Scottish Twin Engines, Oliver the Great Western Engine, Murdoch the Strong Engine (uncle), Arthur the LMS Tank Engine (brother), Spencer the Silver Engine (sometimes), Mavis the Quarry Diesel, BoCo the Metropolitan Vickers Diesel, Bill and Ben the Saddle Tank Engine Twins (good friends and pals), Fergus the Railway Traction Engine, Annie and Clarabel, Old Slow Coach, Stanley, Stepney (son), Bertie, Terence, Butch, Trevor the Traction Engine, Caroline, Harold, Skarloey, Rheneas, Sir Handel, Peter Sam, Rusty, Duncan, Duke, Freddie, Mighty Mac, Luke, Bertram, Ivo Hugh, Molly the Yellow Engine (mother), Rosie, Lady (beautiful magical friend), Belle (beautiful friend), Millie, Stephen, Bash, Dash, and Ferdinand the Logging Locos, Hiro (grandfather), Flynn, Connor, Caitlin, Stafford, Winston the Red Car, Victor, Kevin the Crane, Dennis, Charlie the Purple Engine, Billy, Salty, Porter, Harvey, Elizabeth (sometimes), Cranky (sometimes), Jack, Alfie, Oliver the Excavator, Kelly, Ned, Buster the Steam Roller, Nelson, Paxton, Neville, Captain, Owen, Merrick, Hank, Flora, Pip and Emma, Jinty and Pug, Green Arrow, Iron Duke, Wilbert the Forest Engine, City of Truro
- Enemies: Devious Diesel, 'Arry and Bert, Daisy, Diesel 10, Splatter and Dodge, Stanley (formerly), Spencer the Silver Engine (sometimes), Elizabeth (sometimes), Cranky (sometimes), Bulgy, George, Max and Monty, Den, Dart, Norman, Paxton (only in Day of the Diesels), Sidney, D261, The Horrid Lorries, S.C.Ruffey, Troublesome Trucks
- Likes: Working on the Fat Controller's Railway, being happy, Thomas, being on time, pulling her two coaches.
- Dislikes: Causing confusion and delay, being late with her trains, sharing her shed with Thomas (formerly), seeing Thomas in trouble.