Task: Text Categorization
Input (English): Text:  The London and North Eastern Railway (LNER) Class V2 2-6-2 steam locomotives were designed by Sir Nigel Gresley for express mixed traffic work and built between 1936–1944. The best known is the first of the class 4771 (later 800 and 60800) Green Arrow which is the only preserved example.
Output (English): 6