The calculated distance (air line) between Schwalbach am Taunus and Dortmund is approximately 105 miles respectively 169 kilometers.
By car or train, the actual journey to Dortmund is certainly longer, as only the direct route (as the crow flies) between Schwalbach am Taunus and Dortmund has been calculated here.
Air line (approximately)
169 kilometers
91 nautical miles