The calculated distance (air line) between Fort Gloster and Kāmārhāti is approximately 17 miles respectively 27 kilometers.
By car or train, the actual journey to Kāmārhāti is certainly longer, as only the direct route (as the crow flies) between Fort Gloster and Kāmārhāti has been calculated here.
Air line (approximately)
27 kilometers
15 nautical miles