Papers by Author: Ken Nagashima

Abstract: White layers, which often cause a break of a rail, are generated on its top surface when train wheels spin on it. Therefore its early detection of damaged conditions of the rail that may lead to a break is a critical activity in the rail maintenance. In this study, we have developed an effective method to detect the white layer on the top surface of the rail by using a Superconducting Quantum Interference Device (SQUID).

Abstract: Having undertaken studies into a lightweight and highly efficient superconducting transformer for rolling stock, we developed a prototype with a primary winding, four secondary windings and a tertiary winding using Bi-2223 high temperature superconducting wire. Its primary voltage is 25kV, which is widely adopted as the catenary voltage on the world's high-speed lines. We adopted liquid nitrogen cooling, the weight being 1.71t excluding the refrigerator. The maximum output available to maintain superconductivity is 3.5MVA. We also introduce railways in Japan.