The calculated distance (air line) between Pukchil-lodongjagu and Songnim-ni is approximately 100 miles respectively 160 kilometers.
By car or train, the actual journey to Songnim-ni is certainly longer, as only the direct route (as the crow flies) between Pukchil-lodongjagu and Songnim-ni has been calculated here.
Air line (approximately)
160 kilometers
86 nautical miles