While the locomotive nose cone, the ATC and other technologies were being established, the last major challenge was to develop a chassis that could endure the vibrations caused by high speeds.
Tadashi Matsudaira, who had studied blade vibrations in Zero fighter planes of the Imperial Japanese Navy during World War II, took on this mission.
In an interview years later, Matsudaira said: "When conducting tests with a model, we could see the phenomenon of ‘serpentine motion'—which made a chassis shake from left to right—when it reached speeds in excess of 200 kph."
Matsudaira focused attention on air springs, which he heard were used in automobiles in the United States. The softer the springs, the more comfortable the ride. He realized that the system could be applied to trains by adjusting air pressure. It would have been difficult for engineers working only in the railway field to come up with such a flexible idea. Matsudaira probably acquired an outside-the-box attitude in his navy days, when he willingly adopted new techniques.
Source: Oct. 2, 2000, Yomiuri Shimbun Osaka morning edition