The calculated distance (air line) between Wādī as Sīr and Mafraq is approximately 35 miles respectively 57 kilometers.
By car or train, the actual journey to Mafraq is certainly longer, as only the direct route (as the crow flies) between Wādī as Sīr and Mafraq has been calculated here.
Air line (approximately)
57 kilometers
31 nautical miles