The northern portal is situated at O.S. grid reference SE12381326 and the southern portal at SE12281296, with Netherton Station immediately beyond.
The construction of the tunnel under the village of Netherton proved problematic due to the discovery of a layer of angled shale rock. Collapses were reported in October 1864, August 1865 and November 1866 (the latter caused by heavy rains). The collapse in August 1865 was severe enough to cause subsidence in the village above, leading to the demolition of the house and outbuildings belonging to Jonathan Lunn.
The railway company were able to resolve the issues caused by the instability of the shale rock layer by redesigning the southern portion of the tunnel with curved walls that helped to redistribute the pressure.