The calculated distance (air line) between Wādī as Sīr and Ar Ramthā is approximately 43 miles respectively 70 kilometers.
By car or train, the actual journey to Ar Ramthā is certainly longer, as only the direct route (as the crow flies) between Wādī as Sīr and Ar Ramthā has been calculated here.
Air line (approximately)
70 kilometers
38 nautical miles