E331 series

The E331 series was an experimental articulated city commuter electric multiple unit operated by the East Japan Railway Company from March 2007 to January 2011.
==History==
Incorporating technology from the earlier E993 series set, two seven-car half-sets were delivered to JR East in March 2006; cars 1 to 7 were built by Tokyu Car Corporation (now known as J-TREC) in Yokohama and cars 8 to 14 were built by Kawasaki Heavy Industries in Kobe. Testing would thereafter commence and take place over a year. The set was originally intended for use on the Chūō Line (Rapid) to replace the aging 201 series sets but as the train length was different, its articulated nature being unsuitable with the line's many curves and the line's purpose being for consistent passenger throughput, any plans to put the set on that line were scrapped as there was no place for experimental trains there at the time. The Keiyō Line would ultimately be selected as there would be less switches or curves for the set to navigate.
The set, designated AK1, was introduced experimentally on the Keiyō Line on 18 March 2007 at the start of the revised timetable and was used only on weekend services and other special schedules; AK1 was not used during rush hours as the boarding position for the cars was different from other sets on the line. AK1 was taken out of service on 30 April 2007, about a month after it entered service; cars 8 to 14 were brought back to Kawasaki Heavy Industries's factory on 7 October 2007 for modifications, while cars 1 to 7 were brought back to Tokyu Car Corporation's factory on 25 March 2008. AK1 reentered service on 23 December 2008.
AK1 was taken out of service again around May 2009 and only returned to service on 3 April 2010; a few months later, AK1 was taken out of service yet again on 16 January 2011 and was stored out of service at Shin-Narashino Depot, with no record of use. After three years of storage, AK1 was hauled to Nagano Works for scrapping on 25 March 2014. No E331 series cars have been preserved.
==Design==
The set incorporated various novel design features mostly implemented from the older E993 series experimental electric multiple unit. The 14-car set consists of two seven-car half-sets permanently coupled together and mounted on shared bogies between the diaphragms, for a total of sixteen bogies; cars 7 and 8 had two bogies each, with the remaining cars having shared bogies between the diaphragms.
==Specifications==
Construction was of stainless steel. The set, as mentioned earlier, used various design features as seen on the older E993 series set. Cars 1, 7, 8 and 14 were 16.5 meters long, while the remaining cars were 13.4 meters long. The set's headlights were high-intensity discharge fixtures.
The set's traction system consisted of six insulated gate bipolar transistor variable frequency drives manufactured by Toshiba that were mounted on cars 2, 4, 6, 9, 11 and 13. The train used direct-drive motors in combination with permanent magnetic synchronous motors. The combined use of direct-drive motors and permanent magnetic synchronous motors in the set gave it a droning sound when it accelerated from idle; once the set reached a certain speed, the traction motors made no discernible noise.
Inside the train was an AIMS navigation system, an evolution of the older TIMS navigation system as used on various older sets, such as the E231 series.
==References==
*Wikipedia.org
Category:Unique locomotives
Category:Electric trainsets
Category:JR Group trains
Category:Kawasaki locomotives
Category:Tokyu Car locomotives
Category:Scrapped locomotives