The line was among the first foreseen for electrification with the 25 kV/60 Hz system in South Korea. Works started in 1972, already before the Taebaek Line was completed and officially renamed. The first trial run under the new voltage system in South Korea was conducted with a Class 8000 electric locomotive on the Jeongsan–Gohan section, then called the Gohan Line, on June 9, 1972. Regular electric service started on the long Jecheon–Gohan section on June 20, 1974. The rest of the line was electrified together with the section of the connecting Yeongdong Line until Donghae on the east coast, altogether , on December 5, 1975. At the same time, the Taebaek Triangle Line, a connection built for trains from Jecheon to Donghae to run without reversal at Baeksan, was also put in service.