In lieu of an abstract, here is a brief excerpt of the content:

Sometime after 8:00 p.m. on December 29, 1876, the Lake Shore & Michigan Southern Pacific Express, traveling west out of Erie, Pennsylvania , approached the Ashtabula, Ohio, bridge, just east of the station. The train consisted of three express and one baggage cars, three passenger coaches, and three sleepers hauled by two locomotives—the Columbia and the Socrates. The weather was foul, with snow and sleet driving off of Lake Erie, and the Socrates’s engineman Daniel McGuire slowed his train and cautiously approached the bridge. When he was nearly across, it gave way, dropping all of the train save his own engine about 65 feet into the chasm, where car stoves ensured that the wreckage immediately caught fire. The death toll was eighty-nine, including two officers of the company. It was the worst railroad disaster of the century.1 Ashtabula was what civil engineers called a “square fall”—that is, the bridge failed for lack of strength. Immediately after the event the Ohio legislature commissioned an investigation by a panel of engineers. The bridge was an iron Howe truss that Amasa Stone had designed for the Cleveland & Erie railroad after he had become its president. Stone was an old-time bridge builder who had worked with Howe and patented modifications of the original Howe truss, but who lacked scientific training. The engineers ’ report, which the Engineering News termed “full and satisfactory,” 130 5 EngineeringSuccessandDisaster BridgeDesignandFailure,1840–1900 Does anyone advocate the designing . . . of bridges to withstand the impact of a railroad train . . . ? Are such accidents . . . bridge failures or . . .failures of management ? —Theodore Cooper, Consulting Bridge Engineer, 1889 I believe . . . that the time will come when the failure of an iron bridge from an ordinary accident of train service will be regarded as discreditable to its builder and not excused as a fault of the management. —Charles Stowell, New York State Bridge Engineer, 1889 concluded that Stone’s bridge was in sound condition but suffered from numerous design errors.Among the many such flaws was that the top chord had a factor of safety of only 1.6 when sound engineering practice at that time employed a factor of at least 5. Moreover, the chord consisted of five unconnected beams, which implied that it had little lateral strength. Reviewing this evidence,the eminent bridge engineer Theodore Cooper concluded, “its failure has taught us nothing that we did not know before.”2 Cooper was a member of an emerging fraternity of professional bridge engineers. Educated at Rensselaer Polytechnic Institute, Cooper worked as a railroad engineer and instructor of engineering at the U.S. Naval Academy and then for several bridge companies before launching his long distinguished career as a consulting bridge engineer. For such men, Ashtabula symbolized the problem of bridge failures as they saw it. The old rules of thumb that had dominated American practice since the beginning led to unscientific designs that resulted in square falls. Thus the central problem of bridge safety, in this view, was the need for scientifically informed bridge designers. Of course, bridges collapsed for many other reasons, but these were not engineering failures as Cooper and many other engineers saw matters. Even bridges that were knocked down by a train, for example, did not “fail.”3 A few critics subscribed to a broader conception that saw bridge failures not just in terms of scientifically uninformed engineering but also as the result of design choices that distinguished American from British bridge-building technology and made the former inherently prone to knockdown. Yet even this was too narrow a lens with which to view the problem. Bridge disasters resulted not only from errors, or design choices, but also from a broad array of construction and management practices that characterized nineteenth-century American railroad economics, and from the same problems of monitoring, communication, and control that made all forms of derailment common. TheAmericanSystemofBridgeConstruction As chapters 1 and 2 described, the high cost of capital and comparatively thin traffic induced early American railroads to choose relatively inexpensive construction methods for the permanent way, resulting in adverse consequences for safety. So it was with bridges. In the aftermath of Ashtabula the Engineering News observed,“there are many cases . . . where railroads have been pushed to completion with scanty means, and temporary structures have been erected to be replaced later; but . . . bad times necessitate postponement.” While British railroad builders turned from stone to iron bridge construction in the 1840s, in the United States...

Share