The calculated distance (air line) between Marienthal and Castrop-Rauxel is approximately 181 miles respectively 292 kilometers.
By car or train, the actual journey to Castrop-Rauxel is certainly longer, as only the direct route (as the crow flies) between Marienthal and Castrop-Rauxel has been calculated here.
Air line (approximately)
292 kilometers
157 nautical miles