The short line from Clowne to Killamarsh Junction was a product - just - of the 20th Century. It soon became part of the Great Central's empire. At Spinkhill, the route cut through a hill below Park Hall. Around 500 yards in length, the tunnel is brick-lined and straight except for a curve close to the south portal. Although neither entrance is bricked-up, the northern one is protected by a 30-yard long lagoon which is slightly deeper than the average welly!