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