The calculated distance (air line) between Schwalbach am Taunus and Gelsenkirchen is approximately 113 miles respectively 181 kilometers.
By car or train, the actual journey to Gelsenkirchen is certainly longer, as only the direct route (as the crow flies) between Schwalbach am Taunus and Gelsenkirchen has been calculated here.
Air line (approximately)
181 kilometers
98 nautical miles