TOKYO -- The newest shinkansen bullet train from Japanese rail operator JR East begins test operation Friday, with its top speed expected to exceed the fastest now in service by at least 40 kph.

Green stripes grace the Alfa-X's bluish-silver body, featuring a 22-meter nose on the front car -- the longest for a shinkansen. JR East, formally East Japan Railway, previewed the full 250-meter, 10-car version for the media Thursday at a Miyagi Prefecture facility.

The 360 kph top speed bests the 320 kph of E5 series shinkansen currently running in Japan and TGV bullet trains in France.

The Alfa-X will be tested on the Tohoku shinkansen line between the cities of Sendai and Aomori in northeastern Japan. The trials will take place late at night approximately twice a week. The first phase, to gauge the feasibility of a 360 kph cruising speed, will run until fiscal 2021. Second-phase trials geared toward launching commercial operation will kick off the following year.

The Alfa-X is expected to go into service in fiscal 2030 -- the same year that the Hokkaido shinkansen line is extended to Sapporo from its current ending of Shin-Hakodate-Hokuto Station at the southern tip of the major Japanese island. If the train achieves its touted speed, the trip between Tokyo and Sapporo would be nearly halved to four and a half hours.