The tunnel, between Littleborough and Walsden near Todmorden, was bored beneath the Pennines, a natural obstruction to most forms of traffic.

On 1 March 1841, Summit Tunnel was opened by Sir John Frederick Sigismund Smith; it had cost of £251,000 and 41 workers had died.

Summit Tunnel, between Littleborough and Todmorden[1] is the highest section of the 51-mile (82 km) long Manchester and Leeds Railway, which was built parallel to the Rochdale Canal.

[1] At the peak of construction, a workforce of between 800 and 1,250 men and boys was active, aided by about 100 horses and 13 stationary steam engines, which were used to remove material from the shafts.

At an early stage of track laying, the rails were laid directly onto excavated rock, but conventional wooden sleepers were also used.

[1] Progress on construction was slower than expected; the bedrock and blue shale through which it was bored proved to be harder to excavate than anticipated.

[8] After repairs, the tunnel was officially opened by Sir John Frederick Sigismund Smith, the government inspector of railways on 1 March 1841.

[10] The tunnel closed for the first eight months of 1985 following a fire that generated sufficient heat to vitrify sections of its outer brickwork.

[1][2] The build up of heat in the surrounding ground led to a 'false spring'; many plants produced flowers and buds as the warm soil triggered new growth.

[1][11] On 28 December 2010, a passenger train travelling from Manchester to Leeds was derailed when it struck ice that had fallen onto the tracks from one of the ventilation shafts.