THE

CONWAY AND MENAI

TUBULAR BRIDGES.

In the construction of the Chester and Holyhead Railway twoformidable obstacles had to be overcome. The deep and rapidtidal streams at the Conway and Menai Straits had to be crossedby bridges, which must necessarily be of extraordinary span,and of great strength. No centerings or other substructures,such as are usually resorted to for putting such massive struc-tures together, could be erected.

Under such circumstances the most obvious resource of theengineer was a suspension bridge; but the failure of more thanone attempt had proved the impossibility of running railwaytrains over bridges of that class with safety. Some new expe-dient of engineering was therefore required, and an engineerbold and skilful enough to conceive such an expedient and toapply it. That engineer was found in Mr. Robert Stephenson ,and that expedient is the one, the history of which it is the objectof the following pages to relate.