Japan has started testing world's fastest bullet train, the 'ALFA-X' version of the Shinkansen train, capable of reaching 400 kmph speed. It will be tested twice a week after midnight between Sendai and Aomori, which are around 280 kilometres apart. On entering operation, it will run at up to 360 kmph, outpacing China's Fuxing train, which runs 10 kmph slower.