The calculated distance (air line) between Néa Filadélfeia and Níkaia is approximately 7 miles respectively 11 kilometers.
By car or train, the actual journey to Níkaia is certainly longer, as only the direct route (as the crow flies) between Néa Filadélfeia and Níkaia has been calculated here.
Air line (approximately)
11 kilometers
6 nautical miles