The calculated distance (air line) between Serhetabat and Torbat-e Ḩeydarīyeh is approximately 176 miles respectively 284 kilometers.
By car or train, the actual journey to Torbat-e Ḩeydarīyeh is certainly longer, as only the direct route (as the crow flies) between Serhetabat and Torbat-e Ḩeydarīyeh has been calculated here.
Air line (approximately)
284 kilometers
153 nautical miles