The calculated distance (air line) between Madīnat Khalīfah and Dukhān is approximately 44 miles respectively 71 kilometers.
By car or train, the actual journey to Dukhān is certainly longer, as only the direct route (as the crow flies) between Madīnat Khalīfah and Dukhān has been calculated here.
Air line (approximately)
71 kilometers
38 nautical miles