The Tokaido Shinkansen began operating in 1964 and ran at globally unprecedented speeds of more than 200 kmph. Comparison with the operating speed of aircraft necessitated further improvement of the operating speed of Shinkansen. Nevertheless, there was no improvement until 20 years. During that period, the maximum speed of test cars, the highest technically feasible speed, improved. Rather than technical factors, the following social and organizational factors impeded the improvement of the operating speed. (1) The social factor was the prioritization of environmental countermeasures to improvements in speed because of the noise pollution lawsuits and noise regulation. (2) The organizational factor was the need to secure the slack time due to frequent strikes and delays when Shinkansen was managed by Japan National Railways (JNR). However, around the time of the splitting and privatization of JNR in 1987, noise regulation was relaxed and lawsuits were settled. Furthermore, the labor movement settled down with the privatization of JNR; consequently, labor unions were dismantled. These events resolved preventive factors and led to the improvement of operating speeds.