Thurgoland Tunnel is only a junior relic. It was built in the late 1940s when the Woodhead line was electrified - clearances in the original double bore tunnel (opened by the Sheffield, Ashton-under-Lyne & Manchester Railway in 1845) being too tight to accommodate the necessary overhead equipment.
The concrete-lined structure is curved and now lit, forming part of the Trans Pennine Trail. Next door, its larger sibling has been infilled at its southern end whilst its northern portal is bricked up.
Thurgoland comes in at 312 yards in length.