This theory, attributed to Dr. Peter Lewis, senior lecturer in the Department of Materials Engineering at the Open University, claims that dynamic effects are much more important than had been previously realised (11,12). It is claimed that dynamic effects caused the fatigue failure of the cast iron lugs. The evidence for the dynamic effects is based on the eye witness reports from painters and fitters that the high girders piers oscillated from side to side whenever a train crossed the bridge. On the basis of close inspection of high quality photographs (which show some limited evidence of crack arrest lines) of the failed parts it is claimed that the failure of the cast iron lugs was due to fatigue rather than overstressing. In response to Peter Lewis's paper (11) and book , further research (15) into the matter was undertaken which showed the evidence for fatigue being the main cause of the collapse is weak.