The calculated distance (air line) between Songnim-ni and Ch’ŏngdan-ŭp is approximately 57 miles respectively 92 kilometers.
By car or train, the actual journey to Ch’ŏngdan-ŭp is certainly longer, as only the direct route (as the crow flies) between Songnim-ni and Ch’ŏngdan-ŭp has been calculated here.
Air line (approximately)
92 kilometers
50 nautical miles