'Machine for Dredging Puddle Chambers', Canada, 1860.
© Science Museum / Science & Society Picture Library
Tinted lithograph by Kell Brothers showing a machine used in the construction of the Victoria Bridge at Montreal, Canada. The Victoria Bridge was built to carry the Grand Trunk Railway acros the St Lawrence River. This was necesary as the port of Montreal was closed by ice in the winter and the railway needed to gain acces to Portland, Maine, which remained open throughout the year. The bridge was designed by Robert Stephenson (1803-1859) and was similar in construction to his famous Britannia Tubular Bridge over the Menai Straits in Wales. In both cases Stephenson's solution to the problem of how to carry the weight of trains pulling multiple carriages was to construct a bridge from rectangular iron tubes, through which the trains would run.