North and south portals of Toadmoor Tunnel (SPC 8 44 P1 and SPC8 44 P2), Ambergate, Derbyshire

Summary

Pair of tunnel portals, built 1836-40 for the North Midland Railway by George and Robert Stephenson with Frederick Swanwick.

Description

Pair of tunnel portals, built 1836-40 for the North Midland Railway by George and Robert Stephenson with Frederick Swanwick.

MATERIALS: ashlar and quarry-faced Derbyshire gritstone.

DESCRIPTION: the portals are situated in a cutting. The south portal has an elliptical arch consisting of alternately recessed and projecting ashlar voussoirs, which radiate out into the spandrels. Projecting on either side are raked piers formed of coursed and squared quarry-faced gritstone with punched quoins. The upper course of the piers steps forward to support a bold roll moulding running above the arch. Surmounting it is a low parapet of one large punched course which, together with the roll moulding, acts as a cornice to terminate the structure.

The north portal has a semi-elliptical arch consisting of rusticated ashlar voussoirs and a projecting keystone. The arch is supported by slightly projecting imposts. The spandrels are of rusticated ashlar. Beneath the imposts are concave quarry-faced walls, which continue the ellipse. On either side of the arch are projecting rusticated ashlar piers and heavily recessed quarry-faced wing walls. Above the arch ring is a single ashlar course, truncating the voussoirs, and a moulded string course forming a cornice. Set back from this is a parapet formed of one large ashlar course, which continues round to surmount the wing walls.

The tunnel lining is not included in the listing.

History

The Midland Main Line is the outcome of a number of historic construction phases undertaken by different railway companies. The first two phases were carried out simultaneously between 1836 and 1840 by the North Midland Railway and the Midland Counties Railway. The North Midland Railway, which operated between Derby and Chesterfield and onwards to Rotherham and Leeds, was pre-eminently the work of George (1781-1848) and Robert Stephenson (1803-1859) who, along with Isambard Kingdom Brunel, are the most renowned engineers of this pioneering phase of railway development. They worked closely with the Assistant Engineer, Frederick Swanwick (1810-1885). The railway’s architect Francis Thompson (1808-1895) designed stations and other railway buildings along the line. The less demanding route for the Midland Counties Railway, which ran between Derby and Nottingham to Leicester and on to Rugby, was surveyed by Charles Blacker Vignoles (1793-1875) who was engineer to a large number of railway projects. These two companies (along with the Birmingham & Derby Junction Railway) did not yield the expected profits, partly because of the fierce competition between them. This led to the three companies merging into the Midland Railway in 1844 which constituted the first large scale railway amalgamation. The next part of the line from Leicester to Bedford and on to Hitchin was constructed between 1853 and 1857 by the engineer Charles Liddell (c.1813-1894) and specialist railway architect Charles Henry Driver (1832-1900). In 1862 the decision was made to extend the line from Bedford to London which was again the responsibility of Liddell, except for the final fourteen miles into London and the design of the terminus at St Pancras (listed at Grade I) which was undertaken by William Barlow (1812-1902). Additional routes were then added from Chesterfield to Sheffield in 1870, and from Kettering to Corby in 1879. The most important changes to the infrastructure of the Midland Railway were the rebuilding of its principal stations and the increasing of the line’s capacity, involving the quadrupling of some stretches of the route south of the Trent from the early 1870s to the 1890s.

Toadmoor Tunnel, with its north and south portals, was built between 1836 and 1840 as part of the North Midland Railway. The route from Derby to Chesterfield and onwards to Rotherham and Leeds was surveyed by George Stephenson in 1835, and the Act of Parliament for the construction of the 72 mile line was obtained in 1836. Linked at Derby to the Birmingham & Derby Junction Railway and the Midland Counties Railway, it was to form part of a route from London to Yorkshire and the North East. George Stephenson was joined by his son Robert as joint Chief Engineer on the project in 1837. In order to concentrate on his mineral and mining interests, George relinquished his railway projects in 1839 so it was his son who saw the North Midland through to its completion in 1840. Part of Robert Stephenson’s skill in handling railway projects was his ability to select and manage an able team, and he entrusted much of the engineering design of the North Midland to Frederick Swanwick whose name appears on the surviving contract drawings. The Stephensons, supported by Swanwick, designed the line north from Derby to have gradients no greater than 1 in 250 to suit the low power of contemporary steam locomotives, which meant relegating Sheffield to a link line. To achieve such gradients the line followed the River Derwent as far as Ambergate and then ran through more difficult territory up the valley of the River Amber via Wingfield and Clay Cross to Chesterfield, then over to Rotherham and via Wakefield to Leeds. The notable sequence of picturesque stations along the line was designed by Francis Thompson who was therefore also influential in setting his stamp on the character of the line.

Toadmoor Tunnel, originally known as Hag Wood Tunnel, was designed by George and Robert Stephenson, with their Assistant Engineer Frederick Swanwick. It forms part of a sequence of structures between Derby and Clay Cross which share a common design language. The tunnel was a cut-and-cover construction with a bore that formed a flattened ellipse. The lower part of the tunnel lining was of coursed and squared stone whilst the upper part was brick. This design was adopted to resist the sliding wet shale of the hillside through which the tunnel was built. It was not a complete success as iron braces were subsequently fitted to a 20m section of the tunnel where the lining became distorted.

Reasons for Listing

The pair of tunnel portals, built 1836–40 for the North Midland Railway by George and Robert Stephenson with Frederick Swanwick, is listed at Grade II for the following principal reasons:

* Date: as an early example of a railway structure dating from the pioneering phase in national railway development;

* Historic interest: as part of the North Midland Railway which was designed by George and Robert Stephenson, among the greatest and most influential of all railway engineers, with their assistant Frederick Swanwick;

* Architectural interest: as an example of the consistently high quality design and careful detailing of railway structures completed for the North Midland Railway, the aesthetic quality of which far exceeds the functional and structural requirements;

* Intactness: as a pair of largely unaltered tunnel portals that are remarkably well preserved.

External Links

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