Timber-lattice bridges on railways in the UK: 1840–1870

Timber-lattice bridges have become a forgotten piece of the UK's railway history. Yet these bridges represent a crucial step in the development of iron-lattice and iron-truss bridges. Moreover, these timber bridges also provide further evidence of early interactions between British, Irish and American engineers. This paper looks at the development of timber-lattice bridges in the UK, documenting the designs of individual engineers, their influences and design methods. It will demonstrate that British bridges differed from those of North America. Constructed before engineers had the means of accurately calculating loads acting within structural elements, members were frequently undersized. Consequently, most bridges performed poorly, especially under dynamic loading, resulting in most being altered post-construction. Despite their shortcomings, most bridges did survive long enough to make them financially viable and typically longer than many simplistic forms of timber bridges.