Class 40, also known as The Diesel, D4711 (in the Railway Series), D261 (in the television series), or simply Diesel is a diesel engine who once visited the North Western Railway on loan from British Railways.
There are roughly one-sh*t billion tropes so PLEASE look through them before adding one. Otherwise add what you like. ADDITION: PLEASE read through the trope description provided before submitting something. It's not a huge deal but too often people submit characters that don't fit just because they misinterpreted the title...