Arya- "Actually this "closure due to volcano ruining the line" phenomenon was occurred for only 2 times in Indonesia" Oh ok, I thought because that area is in the "Ring of Fire" that the volcano closure would be more common
Strictly speaking: this phenomenon is quite rare, as most of abandoned rail lines in Indonesia had its route passes through area that does not near enough with volcanoes.
Slightly off-topic but still related with the abandoned rail line, here is the photograph of Krasak River bridge of Ambarawa Line after it was collapsed due to eruption of Mount Merapi in 1975:
(original photo by Malcolm Wilton-Jones)
And returning back to topic:
Remaining of branch line from Barat station (now renamed as Magetan station) to Iswahyudi Airfield used by Indonesian Railways in the past to transport fuel for all of fighter aircrafts allocated there. However, this branchline's ownership fell under the jurisdiction of Indonesian Air Force, just like the now-closed branch line to Abdul Rachman Saleh Airport in Malang.