The Miyauchi to Nagaoka section was electrified in 1947 at 1,500 V DC in conjunction with the electrification of the Joetsu Line , with the Nagaoka to Niigata section electrified in 1962 , the same year the Takasaki to Yokokawa section was commissioned to facilitate the extension to Nagano the following year via the new adhesion line through the Usui Pass mentioned above .