The calculated distance (air line) between Pyeongtaek and Chinch'ŏn is approximately 22 miles respectively 35 kilometers.
By car or train, the actual journey to Chinch'ŏn is certainly longer, as only the direct route (as the crow flies) between Pyeongtaek and Chinch'ŏn has been calculated here.
Air line (approximately)
35 kilometers
19 nautical miles