Tay Rail Bridge
It is memorable for coming after the Dee bridge disaster of 1847, when another cast iron bridge had failed. Cast iron should not have been used in this safety-critical application, and the design seems very strange, using cast iron where timber baulks would have sufficed. The bridge had been built in 1844, well before the Dee accident, and patched with the angle iron in 1853. The discovery of the cracked girder should have alerted engineers to the problem, and all should have been replaced entirely. Cast iron failures remained a problem for many years, culminating in the fall of the Tay Rail Bridge in December, 1879 with over 75 casualties in the passenger express passing over the viaduct at the time the cast iron columns collapsed. The problem did not end there, however, because so much cast iron had been used on the rail network. A cast iron under-bridge failed suddenly under a train during the Inverythan crash in 1882, killing 5 passengers on the train. The event which really focused minds occurred in 1891, when another girder failed under the Brighton express. Although no-one was killed, the furore caused by the Norwood Junction rail accident led to a survey of all under-bridges. Several thousand were eventually found, and ultimately strengthened or replaced.