Boco the Diesel Engine is engine number D5702 who works on Edward's branchline. Allies: Thomas, Edward (mentor), Henry, Gordon, James, Percy, Toby, Duck, Donald & Douglas, Oliver, Emily, Mavis, Daisy (girlfriend), Bill & Ben, Spencer, Sir Topham Hatt (boss), Bertie, Trevor, Terence, Harold, Derek, Salty, Molly, Dennis, Stanley, Bear, Pip & Emma, Skarloey, Rheneas, Sir Handel, Peter Sam, Rusty, Duncan, Freddie, Duke, Mighty Mac, Bertram, Flynn, D261, Hank, Timothy, Mike, Rex, Bert, Den, Dart, Norman, Paxton and Sidney.