were horizontal. Congdon says that he realized the I-beams would carry more live load if they were rotated. Collins, Rogers, and Stone believed workers had installed the beams incorrectly (on their sides). To make the change, Stone had workers cut away portions of each diagonal I-beam's web at the bearing, enabling the web to fit over the lugs. This weakened the new diagonals. There is also some evidence that the angle blocks were damaged while the braces and counter-braces were rotated. The bridge was prestressed again. In every other panel connection, the diagonal braces were fitted to the angle blocks using shims rather than by tightening the vertical posts and putting the diagonals under compression. This meant that the shims carried the weight of a live load, rather than the braces themselves. It is also possible that the shims created uneven contact, causing angle blocks to undergo both bending and shear stress. Nevertheless, the bridge did not sag this time. Upon completion, the bridge was tested by having three locomotives run over the bridge at speed. A second test had the three engines stand still on the bridge. Deflection was minimal and the bridge rebounded satisfactorily. Bridge collapse and fire Blizzard conditions Train No. 5 of the Lake Shore and Michigan Southern Railway, known as The Pacific Express, left Buffalo, New York, at 2 PM on December 29, 1876, 1 hour and 8 minutes behind schedule. A powerful blizzard began hitting northern Ohio, northeast Pennsylvania, and eastern New York two days earlier. More than of snow had already fallen, and winds were creating heavy snowdrifts on the railroad tracks deep in places. The snow was so heavy that, shortly after leaving Buffalo, a second engine was added to help pull the train. The train left Erie, Pennsylvania, at 5:01 PM, an hour and 16 minutes behind schedule. Its two locomotives, Socrates and Columbia, were hauling two baggage cars, two day-passenger coaches, two express coaches, a drawing room car (the "Yokohama"), three sleeper cars (the "Palatine", which originated in New York City and was bound for Chicago; the "City of Buffalo", which originated in Boston and was bound for Chicago; and the "Osceo", a sleeper for passengers going to St. Louis), and a smoking car with about 150 to 200 passengers and 19 crew aboard. Two additional locomotives were needed to push the train away from the station due to the