Since the opening and later extension of the Hokuriku Shinkansen, sections running in parallel have either been discontinued or transferred to third-sector railway companies.

In order to surmount the 552 metre altitude difference between Yokokawa and Karuizawa (which are 10 km (6.2 mi) apart), it then constructed an Abt rack section through the Usui Pass, which opened in 1893, and was double-tracked for 1 km (0.62 mi) from Karuizawa to the top of the rack section.

A German company was selected to provide the engines and General Electric supplied the turbines at the power station.

The electrification allowed for the use of faster and longer trains which reduced journey times and also pollution from the steam engines.

Double-tracking of the remainder of the Takasaki to Kaminagano line was undertaken in sections between 1963 and 1973, commencing with the replacement of the rack mechanism with an adhesion only electrified (1,500 V DC catenary) operation on the 1 in 15 (6.7%) grade.

The rack equipment was initially kept as a contingency, and removed two months after the adhesion-only operation commenced and had proved its reliability.

On 14 March 2015, following the extension of the Hokuriku Shinkansen to Kanazawa, the Nagano to Naoetsu section was also spun off to the following two third-sector operating companies owned primarily by the respective prefectures and municipalities.