Nigel Gresley
Sir Herbert Nigel Gresley (19 June 1876 – 5 April 1941) was an English railway engineer. He was one of Britain's most famous steam locomotive engineers, who rose to become Chief Mechanical Engineer (CME) of the London and North Eastern Railway (LNER). He was the designer of some of the most famous steam locomotives in Britain, including the LNER Class A1 and LNER Class A4 4-6-2 Pacific engines. An A1 Pacific, "Flying Scotsman", was the first steam locomotive officially recorded over 100 mph in passenger service, and an A4, number 4468 "Mallard", still holds the record for being the fastest steam locomotive in the world (126 mph).
4-8-4
The 242F class express passenger locomotives were designed by the "Red Nacional de los Ferrocarriles Españoles" (RENFE) in 1955 and were remarkably well-proportioned. Developed from a preceding Mountain type, they had improved steam passages and developed 30 to 40 per cent more power at medium cut-offs and high speed. Ten of these locomotives were built by "La Maquinista Terrestre y Maritima SA" in Barcelona to burn fuel oil. They had Witte type smoke deflectors and were fitted with a double KylChap (Kylälä-Chapelon) blast-pipe, a Worthington feedwater heater and a "Traitement Integral Armand" (TIA) water-softening device. To increase the comfort of the locomotive crew, the cabs had wooden floors mounted on springs, and the seats of the driver and fireman were also sprung, a very welcome improvement for long runs on poor tracks. These locomotives were painted in a green livery when turned out from the builder's works at Barcelona and were consequently nicknamed "Los Verdes" (The Greens). 
The 242F class was the fastest Spanish steam locomotive. When tested on the line from Barcelona to Tarragona across of practically level and straight line between Vilanova i la Geltrú and San Vincente, a speed exceeding was sustained twice, first with a train of 430 tons and then with a train of 480 tons. High-capacity tests took place between Madrid and Ávila when a train weighing 426 tons, including a dynamometer car, was hauled at sustained speeds of up a gradient of (1 in 286), up a gradient of (1 in 95) and up a gradient of (1 in 44.5). The gross horsepower figures recorded with the dynamometer car were 1790, 2350 and 2320 respectively, the calculated horsepower on the rail being 2600, 3400 and 3580. The latter output translates to about .