The calculated distance (air line) between Shahrak-e Emām Ḩasan and Karaj is approximately 31 miles respectively 50 kilometers.
By car or train, the actual journey to Karaj is certainly longer, as only the direct route (as the crow flies) between Shahrak-e Emām Ḩasan and Karaj has been calculated here.
Air line (approximately)
50 kilometers
27 nautical miles