Overview:The Shinkansen is Japan's bullet train system. Since it debuted 50 years ago as the world's fastest train service, its speed, safety and on-time performance have enabled it to carry more than 6 billion passengers. Today, we explore the secrets behind the Shinkansen, the world's ultimate railway system. Our expert guest is Yoshihiro Akiyama, an engineer who helped design Shinkansen lines in many parts of Japan. And in Plus One, the world's fastest train cleaning crew.