The calculated distance (air line) between Sairang and Chhāgalnāiya is approximately 90 miles respectively 146 kilometers.
By car or train, the actual journey to Chhāgalnāiya is certainly longer, as only the direct route (as the crow flies) between Sairang and Chhāgalnāiya has been calculated here.
Air line (approximately)
146 kilometers
79 nautical miles