The calculated distance (air line) between Sīdī Sālim and Diyarb Najm is approximately 53 miles respectively 85 kilometers.
By car or train, the actual journey to Diyarb Najm is certainly longer, as only the direct route (as the crow flies) between Sīdī Sālim and Diyarb Najm has been calculated here.
Air line (approximately)
85 kilometers
46 nautical miles