This report describes a programme of archaeological building recording prior to and during the restoration of the Paddock Viaduct, Longroyd Lane, Huddersfield, West Yorkshire; centred on SE 1340 1610. The archaeological recording was carried out during 2007 and 2008 and recording took place in tandem with the Wrekin repair programme. The aim of the archaeological survey was to identify and objectively record significant evidence for the original and subsequent historical form and construction of spans 7- 10 of the viaduct. This was achieved by a detailed photographic survey combined with written and drawn field notes. Metallurgical analysis was also undertaken to confirm the date and origin of the metal work. Detailed archive research revealed that the original girder design comprised a close- spaced lattice of narrow wrought iron bars, joined by a single rivet at their intersection. It seems probable that the chosen design, using a close-spaced lattice of wrought iron bars of slender section, represented an attempt to save overall weight compared to the use of iron plate, yet retain a multiplicity of adjacent rivet fixings to minimise the effects of the failure of a single one. Following the development of a national railway network during the 1840s, the weights of individual railway vehicles and locomotives, and the lengths of trains, increased to reflect technological improvements. Many original bridge structures could not support the increased static or dynamic loads imposed by the modern trains, and had to be replaced. The alterations which took place at Paddock Viaduct were evident throughout the spans studied. Recessions within the ashlar bearing shelves revealed positions of the earlier girders and variations of rivet types showed various areas of repair. On top of the replacement of the girders supporting the bridge deck it was also evident that the bridge deck and the wooden walkways had also been replaced. The survey revealed that later additions to the viaduct, such as the new bridge decking, the replacements of bolts and corroded metal, are clearly traceable through the differences in style and technique from the original methods of construction. It was also noted that a detailed archive of architects plans and alterations had been retained within the network rail archives, and these archives enabled alterations to be clearly dated and compared on site.
Mackenzie et al. (Tue,) studied this question.