Main section of Tinsley Viaduct - a twin deck box girder bridge which was built in 1968 to carry both the M1 and A631 Trunk roads across two railway lines. Major strengthening works underway 2003-2005 after new European directive on motorway strength. Date from http://www.highways.gov.uk/roads/projects/motorways/m1/tinsley_viaduct/tinsley_2003/ (accessed 03 March 2005).