Hajime Kawanabe, who developed the ATC, a fundamental system that supports the safety of the Shinkansen, was also an engineer involved in developing balloon bombs for the Imperial Japanese Army. Barred from public service after the war, Kawanabe diligently researched railway signaling systems, writing a steady stream of papers.
The envisaged superexpress train was expected to run at 250 kph, or 70 meters per second—too great a speed for direct human monitoring.
Kawanabe saw the need for an automated speed-control system. He developed a system in which signals set maximum speeds for every three kilometers of track, and trains would brake automatically if they exceeded the limit by even 1 kph. This technology would revolutionize railways around the world.
Source: Oct. 1, 2000, Yomiuri Shimbun Osaka morning edition