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).
High-speed rail
In the early 1950s, the French National Railway started to receive their new powerful CC 7100 electric locomotives, and began to study and evaluate running at higher speeds. In 1954, the CC 7121 hauling a full train achieved a record during a test on standard track. The next year, two specially tuned electric locomotives, the CC 7107 and the prototype BB 9004, broke previous speed records, reaching respectively and , again on standard track. For the first time, was surpassed, allowing the idea of higher speed services to be developed and further engineering studies commenced. Especially, during the 1955 records, a dangerous hunting oscillation, the swaying of the bogies which leads to dynamic instability and potential derailment was discovered. This problem was solved by "yaw dampers" which enabled safe running at high speeds today. Research was also made about "current harnessing" at high-speed by the pantographs, that was solved 20 years later by the Zébulon TGV's prototype.