Gresley’s D49sGresleys D49s 25. 00 Gresleys D49s follows the career of this important class which ran in service between 1927 and 1961. Introduced by the London & North Eastern Railway for intermediate passenger trains, the engines were designed by the world renowned locomotive designer Sir Nigel Gresley. Some of the class members featured poppet valves with rotary cam valve gear. This offered improvements over conventional piston valves. The D49s were employed in