The Class E956 (E956形), branded "ALFA-X" is a ten-car experimental Shinkansen train on order by East Japan Railway Company (JR East) in Japan to test technology to be incorporated into future shinkansen trains operating in service at speeds of up to 360 km/h (225 mph). The name is an acronym for "Advanced Labs for Frontline Activity in rail eXperimentation".

The experimental trainset is intended to be tested at speeds of up to around 400 km/h (250 mph) to evaluate new technologies to be incorporated into new trains to operate in revenue service at speeds of up to 360 km/h (225 mph). It will test new technologies including dampers to reduce vibration and reduce the likelihood of derailment in major earthquakes. It will also test body designs that reduce snow adherence in wintry conditions.

The E956 train will evaluate two different end car nose profiles.

JR East officially announced its plans to build a ten-car ALFA-X train on 4 July 2017. The train is due to be delivered in spring 2019 for extensive testing and evaluation.

The ALFA-X is currently under construction as seen in the great compilation video that's posted in the Videos section, showing many awesome trains being worked on. Check it out at 32:30