Three railway tunnels run parallel to each other and the canal tunnel.
They are level for the whole length, which had the operational benefit of providing the only section of level track on the line where water troughs could be installed to provide steam locomotives with water without the requiring the train to stop.
Both the single-track bores have ventilation shafts at Cote, Flint and Pule Hill and the double-track tunnel is ventilated via three shafts at Brunn Clough, Redbrook and Flint.
Drainage adits interlink with one another, including the canal tunnel, into which water is discharged.

In 1846, work commenced on a railway tunnel for the Huddersfield & Manchester Railway.
It ran parallel to, and to south of the canal tunnel at a slightly higher level.
From the canal tunnel, thirteen adits were driven to facilitate excavating the railway tunnel.
The railway company had bought the canal company to provide access.
 Boats transferred excavated spoil and moved construction materials.
Canal access increased the rate of construction, which took a little over two years; in comparison, the Woodhead Tunnel, which was slightly shorter took seven years to built despite the work being done by the same contractor, Thomas Nicholson.

The tunnel was driven and lined by up to 1,953 navvies working 36 faces.
The tunnel advanced at up to 85 yards (78 m) per week.
Nine men died during its construction.
In 1848, the central single-track tunnel was completed by the London and North Western Railway (L&NWR), who had acquired the Huddersfield & Manchester Railway midway through its construction.
Costing £201,608, the tunnel is 3 miles 57 yards (4,880 m) long.
When opened, trains were accompanied through the tunnel by a pilot man or pilot engine and their re-emergence was communicated between signal boxes situated at either end by a telegraph system devised by Henry Highton.

The 1848 tunnel soon became a bottleneck for rail traffic between Huddersfield and Manchester.
Even before its completion, plans were in consideration for a second tunnel alongside it.
When economic case became clear, Thomas Nelson, who built the first railway tunnel, was awarded the contract.
As with the first tunnel, the canal tunnel was linked to the second by 21 adits which passed underneath Nicholson's tunnel, allowing spoil to be removed by boat.
Construction was disrupted by strike action by tunnellers and bricklayers over disputes about payment and shift length.
In February 1871, the 3-mile-57-yard-long (4,880 m) second rail tunnel, to the south of the first, was opened.

Even two tunnels could not provide sufficient capacity to satisfy demand and in 1890, the L&NWR embarked on providing four tracks on most of the line  which required constructing a twin-track tunnel.

Construction was done under the guidance of AA MacGregor and carried out by 1,800 men who lived in the paper mills at Diggle and 54 wooden huts near the eastern side.
Once again the tunnel was driven from adits, this time 13 adits were connected to the first railway tunnel.
The canal tunnel was extended at the Diggle end to accommodate the third rail tunnel, which ran close past it.
For most of its length, the new bore is to the north of the canal tunnel, but passes over the canal tunnel just inside each tunnel entrance.
When the work was completed,  the tunnel was 3 miles 60 yards (4,883 m) long.
To speed the excavation, 40 breakups were opened using around 120 long tons (120 t) of gelignite.
About 25 million bricks, which were mostly produced locally were used in the tunnel lining.

A 26-foot (7.9 m) unlined section of tunnel collapsed in April 1894 blocking the tunnel for a week.
On 1 August 1894, the new tunnel was passed for use by inspector Major Yorke.
The opening of the double-track tunnel provided additional capacity for the L&NWR, allowing them to temporarily close the single bores for maintenance.
As of 2018, excluding the London Underground, the double-track bore is the fifth-longest UK rail tunnel, after the High Speed 1 tunnels for the Thames Estuary and English Channel, the Severn Tunnel
Three railway tunnels run parallel to each other and the canal tunnel. They are level for the whole length, which had the operational benefit of providing the only section of level track on the line where water troughs could be installed to provide steam locomotives with water without the requiring the train to stop. Both the single-track bores have ventilation shafts at Cote, Flint and Pule Hill and the double-track tunnel is ventilated via three shafts at Brunn Clough, Redbrook and Flint. Drainage adits interlink with one another, including the canal tunnel, into which water is discharged.
In 1846, work commenced on a railway tunnel for the Huddersfield & Manchester Railway. It ran parallel to, and to south of the canal tunnel at a slightly higher level. From the canal tunnel, thirteen adits were driven to facilitate excavating the railway tunnel. The railway company had bought the canal company to provide access.  Boats transferred excavated spoil and moved construction materials. Canal access increased the rate of construction, which took a little over two years; in comparison, the Woodhead Tunnel, which was slightly shorter took seven years to built despite the work being done by the same contractor, Thomas Nicholson.
The tunnel was driven and lined by up to 1,953 navvies working 36 faces. The tunnel advanced at up to 85 yards (78 m) per week. Nine men died during its construction. In 1848, the central single-track tunnel was completed by the London and North Western Railway (L&NWR), who had acquired the Huddersfield & Manchester Railway midway through its construction. Costing £201,608, the tunnel is 3 miles 57 yards (4,880 m) long. When opened, trains were accompanied through the tunnel by a pilot man or pilot engine and their re-emergence was communicated between signal boxes situated at either end by a telegraph system devised by Henry Highton.
The 1848 tunnel soon became a bottleneck for rail traffic between Huddersfield and Manchester. Even before its completion, plans were in consideration for a second tunnel alongside it. When economic case became clear, Thomas Nelson, who built the first railway tunnel, was awarded the contract. As with the first tunnel, the canal tunnel was linked to the second by 21 adits which passed underneath Nicholson's tunnel, allowing spoil to be removed by boat. Construction was disrupted by strike action by tunnellers and bricklayers over disputes about payment and shift length. In February 1871, the 3-mile-57-yard-long (4,880 m) second rail tunnel, to the south of the first, was opened.
Even two tunnels could not provide sufficient capacity to satisfy demand and in 1890, the L&NWR embarked on providing four tracks on most of the line  which required constructing a twin-track tunnel.
Construction was done under the guidance of AA MacGregor and carried out by 1,800 men who lived in the paper mills at Diggle and 54 wooden huts near the eastern side. Once again the tunnel was driven from adits, this time 13 adits were connected to the first railway tunnel. The canal tunnel was extended at the Diggle end to accommodate the third rail tunnel, which ran close past it. For most of its length, the new bore is to the north of the canal tunnel, but passes over the canal tunnel just inside each tunnel entrance. When the work was completed,  the tunnel was 3 miles 60 yards (4,883 m) long. To speed the excavation, 40 breakups were opened using around 120 long tons (120 t) of gelignite. About 25 million bricks, which were mostly produced locally were used in the tunnel lining.
A 26-foot (7.9 m) unlined section of tunnel collapsed in April 1894 blocking the tunnel for a week. On 1 August 1894, the new tunnel was passed for use by inspector Major Yorke. The opening of the double-track tunnel provided additional capacity for the L&NWR, allowing them to temporarily close the single bores for maintenance. As of 2018, excluding the London Underground, the double-track bore is the fifth-longest UK rail tunnel, after the High Speed 1 tunnels for the Thames Estuary and English Channel, the Severn Tunnel
Standedge Tunnels