The calculated distance (air line) between Kau Wa Keng and Tuen Mun is approximately 11 miles respectively 18 kilometers.
By car or train, the actual journey to Tuen Mun is certainly longer, as only the direct route (as the crow flies) between Kau Wa Keng and Tuen Mun has been calculated here.
Air line (approximately)
18 kilometers
10 nautical miles