Apprentice to Robert Stephenson & Company/George Stephenson and helped with construction of Stephenson's Rocket and the Canterbury and Whitstable Railway, drove Stephenson's locomotive 'Invicta' at its opening in 1830; helped with the construction of the York and North Midland Railway; 1845: locomotive superintendent of the Newcastle and Darlington Junction Railway; 1854: N&DJR became part of the North Eastern Railway, Fletcher became its locomotive superintendent until his retirement in 1882.