We have been developing a variable gauge system for through-operation between standard-gauge Shinkansen and narrow-gauge conventional sections since 1994. A Gauge Change Train (GCT), an experimental 3-motor-car electric multiple unit (EMU), was completed for test purposes in autumn 1998 to verify the basic efficiency of this system. It has been designed to run at a maximum speed of over 300 km/h on Shinkansen and 130 km/h on conventional lines under a catenary voltage of 20 kV, 25 kV (50/60 Hz) AC and 1.5 kV DC. It had already been for a year's high-speed endurance evaluation at the Transportation Technology Center in Pueblo, U.S.A. from spring 1999 before being subjected to highspeed and curving performance trials on JR Kyushu and JR Shikoku narrow-gauge lines and gauge change performance and AC-DC section running tests with JR West from 2001 to 2003. We verified running stability at 130km/h on narrow gauge lines and will implement a high-speed performance test on Shinkansen lines in the near future.