The calculated distance (air line) between Akhtubinsk and Tsagan Aman is approximately 56 miles respectively 90 kilometers.
By car or train, the actual journey to Tsagan Aman is certainly longer, as only the direct route (as the crow flies) between Akhtubinsk and Tsagan Aman has been calculated here.
Air line (approximately)
90 kilometers
48 nautical miles