Design and Access and Heritage Statement for the proposed handrail and strengthening works at Whalley railway viaduct

Ref: LNW/NR/2015/122

INTRODUCTION

This statement gives an outline of the principles adopted by the proposal in context to the heritage status of the application site.

Whalley viaduct is a grade II listed structure, receiving its designation in March 1986.

The application seeks listed building consent for the installation of a new hand rail and parapet strengthening works.

SITE CONTEXT

The viaduct falls to the west of the village of Whalley within Lancashire, approximately 0.5km from the village. The structure lies astride the development limits for the settlement and to the edge of the designated Conservation Area.

The viaduct spans across the River Calder, carrying the Daisyfield Junction (Blackburn) to Hellfield railway line. The structure runs partly alongside Broad Lane, and consists of 48 arches, measuring approximately 620m in length. The viaduct is notably a dominate feature within the landscape and is considered to be the longest and largest viaduct in Lancashire.

The viaduct has undergone previous strengthening and maintenance works over the years, including arch strengthening and underpinning works to piers. The structure is considered to be the largest and most prominent engineering feature on the Ribble Valley line.

HISTORIC CONTEXT

The structure was built between 1846 and 1850 for the Blackburn & Bolton Railway Company, in order to increase opportunities on the line. The company were struggling to keep their line open and to make it financially viable, as a result they decided that if the line was extended to the Ribble Valley this would open up the area to the industrial centres of Lancashire, creating opportunities for additional services and much needed traffic.

The viaduct was engineered by Terrance Wolfe Flanagan, and J Withers and provides an interesting feature within the landscape. The structure conveys some unusual characteristics in that the structure was unusually constructed of brick and that 2 arches have been filled in with a brick screen decorated with a large gothic arch, which astride the The Sands, which leads to Whalley Abbey via Broad Lane. Flanagan used Gothic elements here to try to harmonise the structure with the ruins of the nearby Abbey. It is considered that these unusual features of the structure contribute to the historical importance of the viaduct.

Whalley Viaduct ‘gothic arches’

Although the viaduct demonstrates some architectural elements and holds significance for Lancashire it is not the only example of a brick built viaduct from the Victoria era of this scale. viaduct was constructed between 1839 – 1840 measuring 546m; Harringworth viaduct measures 1166m, constructed 1876-1879 and reaching 325m in length was constructed 1846-1848 (Examples below).

Chappel viaduct Harringworth viaduct

Stockport Viaduct

PROPOSAL & JUSTIFICATION

The superstructure supports the two tracks comprising flat bottom rail on steel sleepers and ballast retained between the spandrel walls and string course. Derailment protection over the length of the structure is provided by guard rails located in the four foot of both the Up and Down lines. Masonry stone parapet sections of varying height and length run along the full length of the structure on top of the viaduct's string course to the east and west elevations. The string course overhangs the spandrel walls by approximately 0.12 m and is constructed from similar masonry stone as the parapets (sandstone/gritstone). Historical information suggests the parapet stones are connected to the string course with dowel(s); however, there are no specific details within the available record information. A section of existing handrail is located on top of the west parapet over spans 23 – 32. The structure has an overall width of approximately 8.1 m.

Generally the parapets are in fair condition, with most notable defects identified on the west parapet. In addition, the west parapet particularly, is deformed and misaligned in places, most notably local to span 34, where marked settlement of pier 34 took place around February 2010, and remedial works were subsequently undertaken in 2011.

Network Rail proposes to install a new hand rail along the full length (620m) of the viaduct on each side and to strengthen the existing parapets.

The existing parapets vary in height above ballast level from 0.54 m to 0.84 m and 0.66 to 1.02 on the west and east respectively, which does not meet with current safety standards. The new hand rail will improve safety for railway operatives walking over the viaduct for routine maintenance and inspections. To ensure the parapet can withstand loading from the proposed handrail and that it satisfies current design standards, it is also proposed to strengthen the connection of the existing parapet units to the string course and spandrel wall. The brackets will be designed to carry wind loads on the stone parapet units and transfer to the string course and spandrel below.

In order to achieve this it is proposed to install a steel bracketing system behind the parapet walls and use a concrete stitch adjacent to the string course to tie the section back into the spandrel wall. As parapet stones vary in length from 0.45 m to 2.6 m, it is proposed that a minimum of two brackets are used on each stone parapet up to a length of 1.0 m. For parapet sections of greater lengths, additional brackets will be specified accordingly.

The proposed brackets comprise a single vertical steel angle welded to a base plate providing four fixing points, two into the existing string course and two into the proposed concrete stitch. Vertical dowels into the existing masonry brick spandrel wall and horizontal dowels into the string course ensure transfer of load into the proposed in situ stitch.

The proposed steel handrails will provide a continuous top rail with a minimum height of 1.35 m above the adjacent cess level along the length of the structure. An additional intermediate rail is to be provided along the full length of the structure with a maximum vertical distance from the top rail of 0.5 m. The proposed handrail will be connected directly to the bracketing system to mitigate any interface issues with the existing parapets. The existing cast iron handrail located on the west parapet will be removed to facilitate these works.

ASSESSMENT AGAINST PLANNING POLICY

The relevant planning policy document is the adopted Core Strategy. Key Statement EN5 and policies DMG1 and DME4 provide guidance relating to the conservation of heritage assets. The guidance contained within the Whalley Conservation Area appraisal should also be taken into account.

These policies should be read in conjunction with the National Planning Policy Framework (NPPF) with particular reference to section 12 ‘Conserving and enhancing the historic environment’.

Network Rail understands the importance of approaching these works with care, to ensure that any proposed works at the station do not detract from its listing.

The policies place significance on both preserving and enhancing heritage assets and ensuring works will not be detrimental to the significance of the listed building or the character of the Conservation Area.

The significance of the viaduct falls within a number of elements; the scale and prominence within the landscape promotes the grandeur of the structure, whilst the use of brick conveys its interest within an area constructed predominately of limestone and sandstone. The unusual gothic arches are probably its most interesting element as the only architectural detailing upon this simple (appearance) structure. These gothic arches connect the viaduct to the nearby Whalley Abbey, with gothic influences also echoed within the settlement itself. In addition, importance could be added to the contribution the viaduct had in respect of the industrial growth and import/exportation of goods in Ribble Valley, as this was the primary reason for its original construction.

It is considered that the proposed works to Whalley viaduct will help to preserve the structure, which is referred to as a notable feature of Whalley’s character within the Whalley Conservation Area Appraisal and ensure its continued use as a part of railway infrastructure. The proposal will not result in significant visual harm to the structure and will not influence the gothic arches, which are considered to contribute to the special interest of the viaduct.

It is acknowledged that there is an existing handrail to the western elevation of the viaduct, which stretches between arch no. 23 and no. 32 and is a similar design to the proposal. The proposed handrail will be a kee klamp (or similar) design, which would be sympathetic to the character of the structure. It is considered that the proposed railings will improve the safety standards for worker/operatives or anyone who needs access to the viaduct (possibly including the public in an emergency). Currently the parapets are too low and do not provide adequate safety provision. The proposal will ensure the safe and continued use of the viaduct whilst complying with national and local policies.

The railings are of a modest design and would be functional in its purpose but will be designed as so not to detract from the overall appearance of the listed structure. Whilst it is acknowledged that there will be some change to the existing appearance of the viaduct, this is considered to be minimal given the scale of the viaduct in relation to the proposed railings, and the distance to which the viaduct is usually viewed.

For Network Rail to effectively manage and maintain the rail infrastructure of the 1800s certain alterations to structures are required to make them fit for purpose. When these alterations occur to listed structures the design is always important to ensure that any changes are not detrimental to the character, or the original fabric of the listed structure. With this in mind both national and local planning policy also accept that to keep listed buildings in active use it is understandable that alterations will be made and provided that these changes are sensitive to the original structure they are acceptable.

In addition, it is acknowledged that similar railings have been installed on viaducts along this route without causing significant harm to the historic fabric of the structure and its setting.

CONCLUSION

The proposal considers national and local planning legislation to provide a suitable justification for the alterations to Whalley viaduct. The proposed works will improve safety for railway operatives walking over the viaduct for routine maintenance and inspections which will enable the continued safe operation of the railway.

Taking into account the above policy guidance and the assessment of the proposed work above it is considered that the works would not significantly detract from the historic character or significance of the Listed Building.

It is therefore considered that this application represents an acceptable proposal in terms of design, access and impact on the heritage assets.