The calculated distance (air line) between Shahr-e Bābak and Gerāsh is approximately 179 miles respectively 288 kilometers.
By car or train, the actual journey to Gerāsh is certainly longer, as only the direct route (as the crow flies) between Shahr-e Bābak and Gerāsh has been calculated here.
Air line (approximately)
288 kilometers
156 nautical miles