Warren Girder

I have always thought that the Brinnington railway bridge over the M60 motorway is a particularly fine structure. This Warren girder bridge is the largest single span structure of this type on British railways.

Wikipedia says: The Warren type girder combines strength with economy of materials and can therefore be relatively light. Patented in 1848 by its designers James Warren and Willoughby Theobald Monzani, its structure consists of longitudinal members joined only by angled cross-members, forming alternately inverted equilateral triangle-shaped spaces along its length, ensuring that no individual strut, beam, or tie, is subject to bending or torsional straining forces, but only to tension or compression.