Emily is a Stirling Single tender engine who has a big heart and acts as a sisterly figure to the other engines despite being fussy and impulsive at times. Following her rescue of Gordon from a collapsing bridge and James, Percy and Rebecca from a derailment, she was rewarded with being appointed safety engine, gaining her number twelve with it. She works mostly on the Main Line in odd jobs and mixed traffic duties and once ran the Misty Valley Branch Line. She also has her own set of coaches.