High-speed rail
First above 300&nbsp;km/h developments
#### First above 300 km/h developments

[thumb\|The French CC 7100, 1955 record holder](/wiki/File:SNCF_CC_7102_Pk42_Le_Mee_sur_Seine.jpg "SNCF CC 7102 Pk42 Le Mee sur Seine.jpg")
In the early 1950s, the French National Railway started to receive their new powerful [CC 7100](/wiki/SNCF_Class_CC_7100 "SNCF Class 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](/wiki/Hunting_oscillation "Hunting oscillation"), the swaying of the [bogies](/wiki/Bogie "Bogie") which leads to dynamic instability and potential derailment was discovered. This problem was solved by *[yaw dampers](/wiki/Yaw_damper_%28railroad%29 "Yaw damper (railroad)")* which enabled safe running at high speeds today. Research was also made about "current harnessing" at high\-speed by the pantographs, which was solved 20 years later by the Zébulon [TGV](/wiki/TGV "TGV")'s prototype.


How fast can modern locomotives go compared to those mentioned in the text?