A made-in-Osaka axle supporting a speed of 300 kmph

Cutaway sample of a wheel axle of an N700 Shinkansen train

This is an axle from a N700-model Shinkansen train that can run at a speed of 300 kilometers per hour. The wheels attached to both ends have a diameter of 860 millimeters and are made of a material called high-carbon steel, which has a carbon content of about 0.7 percent. The inclusion of carbon makes the steel harder than even pure iron, and enables preservation of strength. In addition, even greater strength is assured by quenching the tread in contact with the track. All of the wheels of trains running in Japan are made in Osaka by Nippon Steel Corporation.