The Super Conducting Magnetically Levitated High Speed Train, which is about to start service in Japan, has a video of it passing at a speed of more than 500 Kmph.
The project is to start commercial operation of the 286 Km line connecting Tokyo to Nagoya in 2027 (not possible in the current state). The maximum speed at which the train can cover the entire distance in 40 minutes will be 505 Kmph. In the Test Run, the train ran at a speed of 603 Kmph and set a record. Currently, the track is 40 km long.
Super conductivity is the phenomenon in which certain conductors exhibit zero resistance to electricity at extremely cold temperatures. In such a conductor loop, once the current is passed through the loop without the need of a power source, it will continue to flow through the loop. This principle is used in Maglev.
Currently there is a Conventional High Speed Rail service running between Tokyo and Nagoya which covers a distance of 336 km in 1 hour 26 minutes.