Bennerley Viaduct is a 430 metre long wrought iron viaduct on the Nottinghamshire-Derbyshire border. Built-in 1877 to carry the Great Northern Railway line over the Erewash Valley. It survives in an almost unaltered state and is one of only two wrought iron viaducts left in the country. It’s no longer in use.
The viaduct is open to walk across, but I'm not sure if it links to other footpaths of cycle trails. Thanks for your comment.