of the impact manifested itself as a wave, rippling through the decks of the bridge from the American side to the Canadian side and back. From the United States, the New York and Erie Rail Road's Canandaigua and Niagara Falls Railroad and New York Central Railroad's Buffalo and Niagara Falls Railroad crossed over the bridge and reached into Ontario. Similarly, the Great Western Railway in Canada extended its network from Canada into New York. At the time of the bridge's opening, the three railroads were of different gauges: on the New York Central, on the Great Western, and on the Erie. Instead of accommodating three railways side-by-side on a single wide deck, the bridge saved space by overlapping the tracks over each other. This method used only four rails; one pair formed the track for one railway, and the other pair formed another. One rail from each pair would then form the final track. In the first year of the bridge's operation, an average of 30 trains trundled across it each day. Five years later, 45 trains passed over the structure daily. Roebling mandated that the trains be limited to a maximum speed of to ensure absolute safety. He was confident the bridge could handle faster train traffic, but he preferred a safe operation. In his tests the bridge supported a train, bending under the weight. This was within the maximum load of specified in the design of the bridge. The figure was a conservative estimate. The cables and guy-wires could support , and travel journalist Alfred J. Pairpoint commented that it was normal to see trains pass over the bridge without danger. The bridge shook whenever a train trundled over it, although this had no effect on its integrity. When the frequency of passing trains was high, the trembling was noticeable to travelers on the lower deck and proved uncomfortable to some; writer Mark Twain noted, "You drive over to Suspension Bridge and divide your misery between the chances of smashing down two hundred feet into the river below, and the chances of having a railway-train overhead smashing down onto you. Either possibility is discomforting taken by itself, but, mixed together, they amount in the aggregate to positive unhappiness." Despite such commentaries, thousands of people crossed over the bridge safely every day. American engineers regard the Suspension Bridge as a major achievement of efficiency. In a fledgling country where