The calculated distance (air line) between Al Ḩasakah and Al Bāb is approximately 180 miles respectively 289 kilometers.
By car or train, the actual journey to Al Bāb is certainly longer, as only the direct route (as the crow flies) between Al Ḩasakah and Al Bāb has been calculated here.
Air line (approximately)
289 kilometers
156 nautical miles