The calculated distance (air line) between Braunschweig and Oer-Erkenschwick is approximately 145 miles respectively 234 kilometers.
By car or train, the actual journey to Oer-Erkenschwick is certainly longer, as only the direct route (as the crow flies) between Braunschweig and Oer-Erkenschwick has been calculated here.
Air line (approximately)
234 kilometers
126 nautical miles