Driven under Cocker Hill, Stalybridge New Tunnel welcomed eastbound services onto the Micklehurst loop which effectively four-tracked the LNWR's main trans-Pennine route via Diggle, albeit involving alignments on opposite sides of the Tame Valley.
Whilst the tunnel was being constructed, services had to be cancelled in St George's Church, sitting almost above it - explosions shook the foundations, causing cracks to appear. Thanks to the sinking of a construction shaft, headings were driven from one intermediate point as well as both ends. This was later infilled, not retained for ventilation.
The tunnel is 315 yards long, straight and lined throughout in blue brick.
In August 1913, a Leeds-Llandudno express ploughed into the rear of a goods train which was making slow progress through the tunnel. The guard's van and several wagons were wrecked but the guard escaped death by jumping from his van onto the adjacent line. A breakdown gang was summoned to clear the debris.
Although the through line was severed in 1966, a spur through the tunnel remained open until 1976, serving a local power station.
