a proposal that was published in the American Railroad Journal. Mistakenly believing Ellet had won the contract, Roebling wrote to offer his congratulations and requested to be Ellet's assistant. He received a formal reply without any reference to his request, and his subsequent letter was ignored. When Roebling learned that a contractor had won the bid, he successfully applied to be the contractor's chief engineer. Ellet, however, persisted with his tactics and snatched the project away from the contractor; he promoted himself to the bridge company and offered to accept land instead of cash as payment. From then on, Ellet and Roebling became rivals, vying with each other for suspension bridge projects in North America. Roebling learned from their rivalry. His losses to Ellet showed him that he needed to promote himself and gain backers to effectively secure the contracts he desired. When Roebling was called to the Niagara Suspension Bridge project in 1851, he had six suspension structures to his name. He found Ellet's final plan to be impractical; the bridge would have been too heavy and expensive. Roebling had another design in mind: the double-deck bridge he had proposed earlier during the bidding. The lower deck, level with the edge of the chasm, would convey passengers and carriages, and the upper deck, above, would allow fully laden trains to continue their journeys non-stop, albeit at a speed of . Roebling reasoned that the decks and sufficient trusses would form a rigid tube, making the bridge stiffer than a normal suspension bridge. The theory was similar to that of the tubular bridge but implemented at a lower cost. The engineering community was critical of Roebling's project. Robert Stephenson, builder of the tubular Britannia Bridge, was among those shortlisted to complete the Niagara Suspension Bridge before Roebling's selection. Stephenson had submitted a design for a tubular bridge, and in 1859 he built a large and expensive tubular bridge for the Grand Trunk Railway at Montreal, Quebec. The bridge builder then said in derision of Roebling's suspension railway, "If your bridge succeeds, mine is a magnificent blunder." In the face of criticism, Roebling completed the project in four years, using Ellet's bridge as scaffolding. The railway deck was stress-tested by the crossing of the steam engine London at a speed of on March 8, 1855. Ten days later the upper deck of the bridge was officially opened; the lower deck had