Woodhead 3's construction was not without challenge; two roof collapses occurred during 1951, both around the same area. To resolve this weakness, a series of ribbed arches were installed in this section. Reinforced concrete lining, of minimum thickness, was installed throughout the tunnel and an adjacent bypass tunnel was built to improve access and ventilation. The new bore is separated from the nearest tunnel by ; this close proximity was advantageous as it proved convenient during track laying. The old tunnels presented an operational benefit, as water continued to seep into Woodhead 3's predecessors, the water content of the surrounding rock was lowered, resulting in less infiltration into the new tunnel.