Cars 12 and 15 are equipped with PS206 single-arm pantographs. The build details are as shown below. , two (sets R21 and R22) of the original 26 sets are in operation. Three 7-car E3-1000 sets (numbered L51 – L53) were built between 1999 and 2005 for use on Yamagata Shinkansen "Tsubasa" services from 4 December 1999 to augment the 400 series fleet following with the extension of the line to Shinjo. From 2014, a further two sets (L54 and L55) were introduced, reformed from withdrawn Akita Shinkansen E3-0 series "R" sets, to replace the two older sets L51 and L52. The sets are formed as shown below, with five motored ("M") cars and two non-powered trailer ("T") cars, and car 11 at the Tokyo end. Cars 12 and 14 are equipped with PS206 single-arm pantographs. The build details are as shown below. The former identities of the cars reformed into sets L54 and L55 are as shown below. The first of a fleet of twelve new E3-2000 series 7-car sets entered service on Yamagata Shinkansen "Tsubasa" services on 20 December 2008. The new fleet totally replaced the older 400 series trains by summer 2009. The new trains incorporate design improvements, including active suspension, full-colour LED destination indicators, and AC power outlets in all cars. Seating capacity in cars 16 and 17 has been reduced by 4 (one row of seats) compared with the E3-1000 series to provide uniform seating pitch in all cars (seat pitch was previously reduced in non-reserved cars). Cars 12 and 14 are equipped with PS206 single-arm pantographs.  , the E3-2000 series fleet is as follows. From spring 2014, the entire fleet of 15 E3-1000 and E3-2000 series "Tsubasa" sets is scheduled to be reliveried in a new colour scheme designed by industrial designer Ken Okuyama. The new colour scheme uses white, evoking the snow of Mount Zaō, deep purple inspired by the Mandarin duck, the prefectural bird for Yamagata Prefecture, together with yellow and red for the safflower, the prefectural flower of Yamagata Prefecture. The first reliveried set is scheduled to appear in late April. Three sets were repainted by June 2014, and the rest of the fleet of 15 sets was repainted by mid 2016.