The calculated distance (air line) between Pok Fu Lam and Nai Chung is approximately 14 miles respectively 22 kilometers.
By car or train, the actual journey to Nai Chung is certainly longer, as only the direct route (as the crow flies) between Pok Fu Lam and Nai Chung has been calculated here.
Air line (approximately)
22 kilometers
12 nautical miles