A visit to the "Museum Industriekultur Osnabrück" (website) which is adjacent to the headquarters of the Osnabrücker Dampflokfreunde.
From the lower level a tunnel leads to a shaft which used to be worked by a winding engine, today it contains a lift. The former winding engine house is now the main part of the museum. Worth spending an hour or two there; there is a cafe for drinks and snacks. Also see the nearby narrow gauge railway.