The northernmost part of the Chikuhô Honsen can today be seen as a separate line with a shuttle service between Nôgata or Orio and Wakamatsu. The Wakamatsu area on the north side of the Dôkai Bay was once very heavily industrialised, with coal and other freight trains working through from the Nôgata region. The whole Dôkai Bay used to be oriented towards shipping and was marked especially by the huge Yahata Steel Works, constructed 1896-1901.
Now the Wakamatsu-sen, which for itself is 10, 8 km long, is a quiet branch line serving the settlements around Wakamatsu about every half hour. Freight services ended in 1984. The line is still double track, but not electrified. Since operation began of the electric Fukuhoku Yutaka-sen (Kurosaki to Hakata via Orio and Nôgata) the Wakamatsu-sen on its way from Nôgata runs through its own low-level station at Orio.
In October 2016 the Wakamatsu-sen began to test a new battery electric train (type BEC 819), which feeds its batteries from an overhead catenary at the end stops. In March 2017 all trains were turned over to BEC 819 operation.
