follows:—“The suggestion which your kind note contains is quite in accordance with my own feelings and intentions respecting retirement; but I find it a very difficult matter to bring to a close so complicated a connexion in business as that which has been established by twenty-five years of active and arduous professional duty. Comparative retirement is, however, my intention; and I trust that your prayer for the Divine blessing to grant me happiness and quiet comfort will be fulfilled. I cannot but feel deeply grateful to the Great Disposer of events for the success which has hitherto attended my exertions in life; and I trust that the future will also be marked by a continuance of His mercies.”
Although Robert Stephenson, in conformity with this expressed intention, for the most part declined to undertake new business, he did not altogether lay aside his harness; and he lived to repeat his tubular bridges both in Lower Canada and in Egypt. The success of the tubular system, as adopted at Menai and Conway, was such as to recommend it for adoption wherever great span was required; and the peculiar circumstances connected with the navigation of the St. Lawrence and the Nile, may be said to have compelled its adoption in carrying railways across those great rivers.
The Victoria Bridge, of which Robert Stephenson was the designer and chief engineer, is, without exception, the greatest work of the kind in the world. For gigantic proportions and vast length and strength there is nothing to compare with it in ancient or modern times. The entire bridge, with its approaches, is only about sixty yards short of two miles, being five times longer than the Britannia across the Menai Straits, seven and a half times longer than Waterloo Bridge, and more than ten times longer than the new Chelsea Bridge across the Thames! It has not less than twenty-four spans of 242 feet each, and one great central span—itself an immense bridge—of 330 feet. The road is carried within iron tubes 60 feet above the level of
the St. Lawrence, which runs beneath at a speed of about ten miles an hour, and in winter brings down the ice of two thousand square miles of lakes and rivers, with their numerous tributaries. The weight of iron in the tubes is about ten thousand tons, supported on massive piers, which contain, some six, and others ten thousand tons of solid masonry.
So gigantic a work, involving so heavy an expenditure—about £1,300,000—was not projected without sufficient cause. The Grand Trunk Railway of Canada, upwards of 1200 miles in length, traverses British North America from the shores of the Atlantic to the rich prairie country of the Far West. It opens up a vast extent of fertile territory for future immigration, and provides a ready means for transporting the varied products of the Western States to the seaboard. So long as the St. Lawrence was relied upon, the inhabitants along the Great Valley were precluded from communication with each other for nearly six months of the year, during which the navigation was closed by the ice.
The Grand Trunk Railway was designed to furnish a line of communication through this great district at all seasons; following the course of the St. Lawrence along its north bank, and uniting the principal towns of Canada. But stopping short on the north shore, it was still an incomplete work; unconnected, except by a dangerous and often impracticable ferry, with Montreal, the capital of the province, and shut off from connection with the United States, as well as with the coast to which the commerce of Canada naturally tends. Without a bridge at Montreal, therefore, it was felt that the system of Canadian railway communication would have been incomplete, and the benefits of the Grand Trunk Railway in a great measure nugatory.
As early as 1846 the construction of a bridge across the St. Lawrence at Montreal was strongly advocated by the local press for the purpose of directly connecting that city with the then projected Atlantic and St. Lawrence Railway. A survey of the bridge was made, and the
scheme was reported to be practicable. A period of colonial depression, however, intervened, and although the project was not lost sight of, it was not until 1852, when the Grand Trunk Railway Company began their operations, that there seemed to be any reasonable prospect of its being carried out. In that year, Mr. A. M. Ross—who had superintended, under Robert Stephenson, the construction of the tubular bridge over the Conway—visited Canada, and inspected the site of the proposed bridge, when he readily arrived at the conclusion that a like structure was suitable for the crossing of the St. Lawrence. He returned to England to confer with Robert Stephenson on the subject, and the result was the plan of the Victoria Bridge, of which Robert Stephenson was the designer, and Mr. A. M. Ross the joint and resident engineer.
The particular kind of structure to be adopted, however, formed the subject of much preliminary discussion. Even after the design of a tubular bridge had been adopted, and the piers were commenced, the plan was made the subject of severe criticism, on the ground of its alleged excessive cost. It therefore became necessary for Mr. Stephenson to vindicate the propriety of his design in a report to the directors of the railway, in which he satisfactorily proved that as respected strength, efficiency, and economy, with a view to permanency, the plan of the Victoria Bridge was unimpeachable. There were various methods proposed for spanning the St. Lawrence. The suspension bridge, such as that over the river Niagara, was found inapplicable for several reasons, but chiefly because of its defective rigidity, which greatly limited the speed and weight of the trains, and consequently the amount of traffic which could be passed over such a bridge. Thus, taking the length of the Victoria Bridge into account, it was found that not more than 20 trains could pass within the 24 hours, a number insufficient for the accommodation of the anticipated traffic. To introduce such an amount of material into the suspension bridge as would supply increased
rigidity, would only be approximating to the original beam, and neutralizing any advantages in point of cheapness which might be derivable from this form of structure, without securing the essential stiffness and strength. Iron arches were also considered inapplicable, because of the large headway required for the passage of the ice in winter, and the necessity which existed for keeping the springing of the arches clear of the water-line. This would have involved the raising of the entire road, and a largely increased expenditure on the upper works. The question was therefore reduced to the consideration of the kind of horizontal beam or girder to be employed.