The calculated distance (air line) between Qaşr al Qarabūllī and Tripoli is approximately 32 miles respectively 52 kilometers.
By car or train, the actual journey to Tripoli is certainly longer, as only the direct route (as the crow flies) between Qaşr al Qarabūllī and Tripoli has been calculated here.
Air line (approximately)
52 kilometers
28 nautical miles