  k V ▁AC ▁in ▁April ▁ 2 0 1 6 . ▁▁ 3 0 0 0 ▁V ▁DC ▁The ▁elect r ification ▁of ▁the ▁How rah - B urd wan ▁section ▁of ▁the ▁Eastern ▁Railway ▁at ▁ 3 0 0 0 ▁V ▁DC ▁was ▁completed ▁in ▁ 1 9 5 8 . ▁The ▁first ▁ 3 0 0 0   V ▁DC ▁EM U ▁service ▁began ▁on ▁the ▁How rah - She or aph uli ▁section ▁on ▁ 1 4 ▁December ▁ 1 9 5 7 . ▁The ▁last ▁section ▁of ▁ 3 0 0 0 ▁V ▁DC ▁in ▁India , ▁from ▁How rah ▁to ▁Bur d wan , ▁was ▁upgrad ed ▁to ▁ 2 5 ▁k V ▁AC ▁in ▁ 1 9 6 8 . ▁▁ 2 5 ▁k V ▁AC ▁ ▁The ▁ 2 5 ▁k V ▁AC ▁system ▁emer ged ▁as ▁an ▁econom ical ▁form ▁of ▁elect r ification ▁as ▁a ▁result ▁of ▁research ▁and ▁tri als ▁in ▁Europe , ▁particularly ▁on ▁French ▁Rail ways ▁( SN CF ). ▁Indian ▁Rail ways ▁decided ▁to ▁adopt ▁the ▁ 2 5 ▁k V ▁AC ▁system ▁of ▁elect r ification ▁as ▁a ▁standard ▁in ▁ 1 9 5 7 , ▁with ▁SN CF ▁their ▁consult ant ▁in ▁the ▁early ▁stages , ▁later ▁taken ▁over ▁by ▁the ▁ 5 0 ▁c / s ▁Group . ▁The ▁joint ▁vent ure ▁was ▁founded ▁in ▁ 1 9 5 4 ▁by ▁several ▁European ▁railway ▁manufact ur ers ▁and ▁was ▁dedicated ▁to ▁the ▁development ▁and ▁construction ▁of