Takamori Line was a local line in Kyusyuu Island and located at the edge of huge volcano Mount Aso. The line ran through mountainous area with deep valleys and some bridges of the line were very high. Actually No.1 Shirakawa Bridge was the highest railway bridge in Japan then. The line was planed to be connected to Hinokage Line, but it never happened.
C12 class was used on both lines.