Niagara Falls Suspension Bridge

Suspension Bridge
Hand-colored lithograph of the Suspension Bridge as seen from the American side: the bridge's architecture, the distant Niagara Falls, and the Maid of the Mist below the bridge are visible. (Charles Parsons, 1857.)
Coordinates	43°06′33″N 79°03′30″W
Carries	Trains and carriages
Crosses	Niagara River
Locale	Niagara Falls, New York and Niagara Falls, Ontario
Official name	International Suspension Bridge (United States) Niagara Falls Suspension Bridge (Canada)
Maintained by	Niagara Falls International Bridge Company (United States) Niagara Falls Suspension Bridge Company (Canada)
Characteristics
Design	Suspension bridge
Material	Wood, limestone, and steel cables (gradually replaced with iron and steel)
Longest span	822 feet (251 m)
Load limit	450 short tons (410 t)
Clearance below	250 feet (76 m)
History
Designer	Charles Ellet, Jr. (1847–48) John A. Roebling (1851–55)
Opened	August 1, 1848 (footbridge) March 18, 1855
Closed	August 27, 1897
Statistics
Daily traffic	45 trains per day (1860)
Toll	25 cents per person, 50 cents per horse-carriage, 50 cents per carriage passenger (1873)
Location

The Niagara Falls Suspension Bridge was a suspension bridge north of Niagara Falls. Connecting Niagara Falls, Ontario to Niagara Falls, New York, it carried mixed traffic across its two decks across the Niagara River; trains crossed over the river by way of the bridge's upper deck while pedestrians and carriages took to the lower deck. As the bridge was a collaborative effort between two companies of two countries, it was also known as the International Suspension Bridge for its American company. The bridge had other names including the Niagara Railway Suspension Bridge and Niagara Suspension Bridge, but the most common and definitive was simply the Suspension Bridge.

The Suspension Bridge was part of Canadian politician William Hamilton Merritt's vision to promote trade within his country and with its neighbour the United States. Merritt and company engaged several well known civil engineers to build and maintain the bridge. Charles Ellet, Jr. was first hired to construct the bridge. Aiming for publicity and to secure a line between the shores of the Niagara River, Ellet organized a kite flying contest. A young boy, Homan Walsh, succeeded in flying a kite across the 800-foot (240 m) chasm and tying the line to both sides. Heavier cables were tied to the kite string and successively pulled across the gap. A footbridge was completed in 1848, and the lucrative toll collected from the heavy traffic across it led to a dispute between Ellet and the bridge companies. Ellet left the project, and the companies hired John Augustus Roebling to complete it. Roebling had a different design for the bridge and used the footbridge as scaffolding to build his double-decked bridge. By 1854 his bridge was nearly complete; the lower deck was opened for pedestrian and carriage travel. The official opening of the completed bridge was on March 18, 1855. A fully-laden passenger train drove over the span on the upper deck at 5 miles per hour (8.0 km/h), making the structure the first suspension bridge in the world to handle moving trains.

The Suspension Bridge brought a large influx of trade and tourists into the region around the Niagara Falls. Small towns at the ends of the bridge quickly grew, and they were integrated into the Niagara Falls cities. The Suspension Bridge was acclaimed as a marvel of engineering and a man-made wonder that must be viewed along with the natural wonder of the falls. Daredevils walked across tightropes against the backdrop of the falls and, in mid-crossing, performed stunts for audiences on the Suspension Bridge. In the time leading up to the American Civil War, the Suspension Bridge was one of the four main routes of the Underground Railroad, a clandestine system helping slaves in the United States escape to freedom in Canada. After the war, Americans looked to the bridge as a symbol to inspire them in the rebuilding of their country.

Throughout its years of service, the Suspension Bridge stood strong, disproving general opinion that suspension bridges were frail and overcoming concerns induced by the 1854 collapse of the Wheeling Suspension Bridge. The bridge's wooden structures and limestone towers gradually decayed over time and were replaced with steel and iron versions by 1886. The bridge itself was finally replaced by the Steel Arch Bridge, which was later renamed the Whirlpool Rapids Bridge, on August 27, 1897. On dismantlement the Suspension Bridge's wire cables were found to be as strong as they were on the day the bridge itself was built, a testament to its strength and design.

Conception and building

In the middle of the 19th century, the hinterlands of the North American East Coast were being opened up at a rapid pace; colonists moved further inland, pushing back the wilderness and establishing settlements that grew into towns and cities. As they grew, these centers of civilization demanded for more and better trade routes to other settlements. Canadian entrepreneur and politician, William Hamilton Merritt, was a major contributor to the establishment of several such routes in his country. His primary focus was on the lakes and the dredging of waterways to open up trade between the lake cities. The entrepreneur also showed interest in railroads, envisioning a network that connected cities on both sides of the United States-Canadian border from the Atlantic coast on the East to the new territories in the West. Merrit's dream would lead to the creation of a man-made wonder, a railway suspension bridge, that spanned the Niagara River alongside the river's own natural wonder of the falls.

William Hamilton Merrit was the chief proponent for the Suspension Bridge, actively campaigning to obtain charters for the bridge.

Merritt's vision for the Niagara Suspension Bridge was conceived at the Niagara River itself.^[a] In the summer of 1844 while taking a picnic on the shores of the river, near the then town of Clifton, Merrit read a letter from his sons to his wife. The younger Merritts were touring Europe and visited the town of Fribourg, Switzerland. Amazed by the Freiburg Suspension Bridge, they wrote to their parents, speaking of the wonders of the bridge in eloquent terms. Their writing had such an impression on their mother that she wondered aloud if such a suspension bridge could be built across the Niagara. Her comment moved Merritt and inspired him to realize that vision. He actively wrote to the relevant authorities, including the Queen of England, asking for charters to start the project to build the suspension bridge. Merrit's efforts were rewarded in 1846; the state of New York and the government of Canada approved the charters for formation of the Niagara Falls International Bridge Company and the Niagara Falls Suspension Bridge Company, respectively.

In the years before the first bridge was built over the Niagara River, the river was crossed entirely by boats. Powered by steam engines, the vessels ferried people and carriages across the raging river at calmer points of the water. One of these vessels was the Maid of the Mist, the first tourist boat to ply the waters of the Niagara River. Named after a local legend, the steamer first started service in 1846. Launching from a point 2 miles (3.2 km) below the Horseshoe Falls, it chugged up to the base of the falls, offering a close-up view of the natural wonder to its passengers, before moving to the opposite shore. The site for the Suspension Bridge was half a mile (0.8 km) away from the Maid of of the Mist's landings. The selection of the bridge site was based more on aesthetics than technical ease; it was the narrowest point of the gorge—800 feet (240 m) across and 230 feet (70 m) deep—that allowed a full view of the falls from the American side.^[b]

After the bridge companies were founded, they invited engineers to submit plans and cost estimates for a suspension bridge that carried a railway. The invitation was met with skepticism among the engineering community. At that time, there was not a suspension bridge that could allow a train to pass over safely. While the Europeans were erecting suspension bridges by the hundreds, the Americans mostly ignored them out of safety concerns; in 1831 Sir Samuel Brown's Broughton Suspension Bridge in Britain collapsed under the marching feet of a troop of soldiers, sending those on its deck into the River Irwell. Furthermore, many American bridges had collapsed without experiencing the weight and pressure equivalent to railroad traffic, and American engineers feared that a bridge carrying a railroad would likely fail, more so for a suspension bridge.

Only four engineers responded: Edward Serrell, Samuel Keefer, Charles Ellet, Jr., and John Augustus Roebling. All submitted designs for a suspension bridge. At the time of the bidding, Ellet and Roebling were acknowledged as masters of suspension bridge building in America. Roebling submitted two designs, a conservative single-deck suspension bridge and a double-decked version, both with meticulous calculations and drawings. Instead of relying solely on submissions, Charles Ellet, Jr. took a proactive approach. When he got wind of the project in 1845, he wrote to Charles B. Stuart, chief engineer of the Great Western Railway,^[c] boldly proclaiming that he can build a bridge for any likely purpose across the Niagara. After the charters had been obtained, Ellet helped Stuart to sell the bridge companies' stock and offered to buy US$30,000 worth of stock himself. His efforts gained him the $190,000 bridge contract on November 9, 1847.

Charles Ellet, Jr.

Charles Ellet, Jr., the first American-born civil engineer formally educated in Europe, campaigned for suspension bridges in United States.

Growing up on a farm in Pennsylvania, Charles Ellet, Jr. scraped through odd jobs, saving enough money to finance him an education at the École Polytechnique in France. After graduation he toured Europe before returning to the United States as the only native American with a formal education in engineering. Ellet announced his ambitions to build suspension bridges in his country of birth by proposing to span the Potomac River with such a structure. His proposal was ignored; few were willing to heed a young, inexperienced and impetuous engineer. To gain experience, Ellet started to work on railroads and canals, and later became the chief engineer on the James River and Kanawaha Canal project. He further built up his reputation by contributing suspension bridge articles to noted engineering journals, such as American Railroad Journal; eventually, Ellet got to build his first suspension bridge over the Schuylkill River, Pennsylvania, in 1842.

Ellet had the looks of an actor, which was complemented by his entertaining oratorical skills. He took advantage of these characteristics, engaging in showmanship and dramatics to market his proposals. These skills proved helpful in winning him attention and raising his profile both in the public and industry. However, his imperiousness also ruffled the feathers of people, leading to conflicts. Nonetheless, his capability to promote himself had won him the contracts for the Suspension Bridge and the later Wheeling Suspension Bridge; the Wheeling contract was won in July 1847 while Ellet's plan for the Niagara Suspension Bridge was in its initial stages of construction. Ellet's initial design for the Suspension Bridge placed all forms of transportation on a single deck. In the middle of the deck was the railway track, sandwiched between carriageways and footpaths on the outer sides. Moreover, trains would not go over the bridge; their cars would be disconnected from the heavy locomotives and pulled across the bridge by horses, cables, or lighter 6-short-ton (5.4 t) engines. Before the construction could begin, Ellet faced the problem of all suspension bridge construction: getting a line across the gap.

Ellet's brainstorming sessions with his men raised several ideas that could enable a line to be suspended across the gorge; these included firing cannon balls with the line attached, towing it across the river with a steamer, and tying it to a rocket that is then launched across the gorge. Ultimately the bridge engineer went ahead with an idea inspired by Benjamin Franklin's experiment with a kite. It was similar to 15th century inventor Leonardo da Vinci's plan to span a gap. Ellet also took the opportunity to generate publicity for his project. Organizing a kite-flying contest, he offered $5^[d] to any boy who flies a kite across the gorge and secures the kite string to the other side. The youths from nearby towns flocked in to participate. Unlike the other boys who flew their kites from the United States side of the gorge, 15-year-old Homan Walsh^[e] crossed the river by a ferry upstream and walked to the Canadian side of the bridge site. He almost succeeded on his first attempt: his kite flew across but crashed just short of the shore. After resting several days at a friend's house, Walsh finally got his kite across the gorge and secured its line to a tree.

Charles Ellet and his team tied a heavier line to the kite string and pulled the joined lines across. They pulled successive heavier and stronger lines across in this fashion until the final bridge cable—0.875 inches (2.22 cm) thick—was hanging across the gorge. The cable was suspended between two wooden towers 40 feet (12 m) feet tall, and on it was attached an iron basket. Ellet planned to use this system as a basket ferry to shuttle workers and materials across the gorge, saving the time that would otherwise have been spent on land and ferry travel. Through media coverage and word-of-mouth, many people had known of Ellet's efforts and flocked to the site to watch the construction. On March 13, 1848, the system was completed, and the team planned to test it by pulling the empty basket across. They hit a snag when the basket kept getting stuck halfway and could not move ahead. Pulling back the basket, Ellet decided to assure the watching crowd that the system was workable. He stepped into the basket, and it moved towards the opposite shore. Reaching the problematic spot Ellet spotted the issue; the basket's rollers could not pass over a portion of the cable that had been accidentally flattened during the construction. He fixed the problem and proceeded to cross to the Canadian side and back, becoming the first person to cross the gorge. Although the bridge companies had prohibited Ellet from collecting tolls, he charged each person $1.00^[f] for the chance to "observe first hand the engineering wonder of bridging the Niagara". On certain days, the basket ferry conveyed up to 125 people across the gorge.

Continuing his construction, Ellet built an 8-foot (2.4 m) wide footbridge out of the the towers and cable of the basket ferry. The bridge builder inaugurated the footbridge in his typical fashion on July 29, 1848; standing in his horse-buggy like a gladiator in his chariot, Ellet sped across the bridge, which had railings for only a third of its length at that time. His stunt garnered further publicity for the bridge, and the toll collected from the span proved lucrative; $5,000 was collected in less than a year since its official opening on August 1, 1848. Disputes arose between the bridge companies and Ellet over their shares of the money, and their relations turned bitter. The companies charged that Ellet was late in his schedule and withheld payment. Ellet retaliated by mounting cannons at the footbridge to claim ownership over it. In the end the matter went to court. The bridge companies paid $10,000 to Charles Ellet, and he left the project to work full-time on the Wheeling Suspension Bridge.

The Niagara Suspension Bridge project was in hiatus for three years before the bridge companies engaged another renowned civil engineer, John Augustus Roebling, to complete it. The delay caused Roebling to miss out the honor of building the first permanent bridge to span the Niagara; Serrell completed the Lewiston Suspension bridge in 1851. Roebling would, however, achieve several other honors in building his Niagara Railway Suspension Bridge.

John Augustus Roebling

John Augustus Roebling built several prominent suspension bridges in the United States, earning him the esteem of the engineering community.

Born in Germany, John Augustus Roebling graduated from the Berlin Bauakademie in 1826, receiving a diploma in engineering from the Royal Polytechnical Institute. He initially worked for the German government but resigned after tiring of the bureaucracy. He left for the United States in 1830 and arrived with his brother in Philadelphia on August 6, 1831. Instead of continuing an engineering profession, he took up farming for a living. After five years he married a tailor's daughter and had eight children with her over the next decade. Agrarian work proved less than fulfilling to John Roebling, and in 1837, after the death of his brother and the birth of his first child, he turned back to engineering.

Roebling first signed on as a surveyor for the Sandy and Beaver Canal, launching his career with a string of canal and railroad projects. Aside from writing numerous articles in engineering journals, Roebling designed his own wire cables and set up his own company to manufacture them; the John A. Roebling Company was the first wire rope manufacturer in the United States. Gradually building up a name for himself as a civil engineer, Roebling finally got to build suspension bridges. His first bridge was the Allegheny Suspension Aqueduct in Pittsburgh. The structure, completed in 1845, was the first supension aqueduct in the world and the first large American suspension bridge that had multiple spans. Furthermore, it was the first suspension structure to be built with modern cable spinning techniques—Roebling's own invention. Earlier bridge building techniques involved firstly fabricating the main cables at a factory, transporting them to the bridge site, and then stretching the heavy cables over the gap to erect them over the bridge. Roebling, in his investigations of wire ropes, thought up and patented a new construction method for these main cables. Guide wires were first fixed across the gap. Pulleys ran along these guides, pulling individual wires with them. As the pulleys go back and forth, the wires were spun into thicker strands, which were subsequently spun into the main cables. The cables supported themselves and the proportional weight of the bridge as they were being formed. The method became the standard for suspension bridge construction, remaining unchanged for many years. In the 20th century, suspension bridges were still built with this pulley winding system, albeit with more sophisticated equipment.

John Roebling was a contrasting figure to Charles Ellet. Where Ellet embellished his proposals with fanciful words and deeds, Roebling presented papers filled with meticulous calculations and drawings. The elder engineer was stern and driven to achieve things, taking a scientific approach in all interests. Rarely did he show emotions in his dealings, even to his closest associates. The man was, however, dared to confront his detractors and make bold proclaimations on his work. He openly called the suspension bridges in Europe weak, even targeting Ellet's and Stephenson's works. On his own works, he announced his Brooklyn Bridge, when completed, "will not only be the greatest bridge in existence, but it will be the greatest engineering work of this continent, and of the age." Roebling and Ellet could have been a team. Early in their careers, both men were aiming for the contract to build a suspension bridge over the Shyulkill river, Pennsylvanna. After Ellet's proposal was published in the American Railroad Journal, Roebling wrote to offer his congratulations and request to be Ellet's assistant; Roebling was under the misconception that Ellet had won the contract. Ellet gave a formal reply without accepting Roebling's offer and ignored his subsequent letter. The two became rivals, vying with each other for suspension bridge projects in North America. Roebling learnt from their rivalry. His losses to Ellet showed him that he needed to promote himself and gain backers to effectively secure the contracts he desire.

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.^[g] The lower deck, level with the edge of the chasm, would convey passengers and carriages, while the upper deck, 18 feet (5.5 m) above, would allow fully laden trains to continue their journeys non-stop, albeit at a speed of 5 miles per hour (8.0 km/h). 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 short-listed 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. Stephenson 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 footbridge as scaffolding. The railway deck was stress tested by the crossing of a 23-short-ton (21 t) steam engine London at a speed of 8 miles per hour (13 km/h) on March 8, 1855. Ten days later the upper deck of the bridge was officially opened; the lower deck was opened to the public a year ealier. As the first commercial passenger train trundled over the bridge, the two countries of North America were finally connected by railroad across the Niagara River. The successful crossings of these and later trains made Roebling's Suspension Bridge the first working suspension railway bridge in history.^[h]

Engineering

Roebling's bridge had two limestone towers on each side of the gorge supporting it. These Egyptian-style towers stood 88 feet (27 m) tall on the American side and 78 feet (24 m) tall on the Canadian shore. With their foundations 28 feet (8.5 m) in the earth, the limestone structures could support up to 12 million pounds (5.4 million kg) of pressure. Four 10.5-inch (27 cm) thick main cables held up the bridge; two cables ran through iron saddles at the top of each tower. Each cable comprised 3,059 wires that were spun with Roebling's patented technique used in his Allegheny Suspension Aqueduct. The ends of each cable were secured to 6-square-foot (0.56 m²) cast-iron plates sunk 20–30 feet (6.1–9.1 m) deep in the bedrock. Support lines hung down from iron clamps that encircled the main cables, and held up the decks. Deep trusses line the sides of the bridge, a design till then unseen on a large suspension bridge,^[i] joining the two decks and making the structure seem like a cage. The trussed sides along with the upper and lower decks, which spanned 825 feet (251 m), formed a "hollow straight beam", reinforcing the rigidity of the bridge.

The Suspension Bridge was further stiffened by guy-wires running from its upper deck to the top of its towers. Criticism of suspension bridges was growing after the Wheeling Suspension Bridge had collapsed under strong winds in 1854. To address these concerns, Roebling added more guy-wires to secure the lower deck to the shores below. Roebling's efforts ensured that his Suspension Bridge remained standing while other suspension bridges across the Niagara River collapsed from strong winds.^[j] Although he was not the first engineer to appreciate the need for a suspension bridge to be sufficiently rigid or to implement the methods to do so, Roebling was the first to understand the principles behind the methods and combine them in the building of a suspension bridge. Roebling proved that despite popular opinion, properly built suspension bridges can safely support the passage of heavy railway traffic. The engineer's combination of stiffening methods created the first modern suspension bridge. Such was the rigidity of the Suspension Bridge that it withstood the shockwave caused by the nearby fall of a 5,000-short-ton (4,500 t) mass of rock in 1863; the force of the impact manifested itself as a wave, passing through the decks of the bridge from the American side to the Canadian side and back.

The Suspension Bridge used combinations of four rails to serve three different railroads.

On the United States side, the bridge connected to the New York Central Railroad's Buffalo and Niagara Falls Railroad and the New York and Erie Rail Road's Canandaigua and Niagara Falls Railroad. The Great Western Railway ran west from the Canadian approach. At the time of the bridge's opening, the three railroads were of three different gauges: 4 ft 8+1⁄2 in (1,435 mm) standard gauge on the New York Central, 66 on the Great Western, and 72 on the Erie. Instead of making a deck wide enough to accomodate the three railways side-by-side, 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 its operation, an average of 30 trains passed over the bridge each day. Five years later 45 trains passed over it daily.

Roebling mandated that the trains be limited to a maximum speed of 5 miles per hour (8.0 km/h) to insure absolute safety. He was confident the bridge could handle trains moving at a faster speed, but he would rather have a safe operation. In his tests the bridge supported a 326-short-ton (296 t) train, bending 10.5 inches (27 cm) under the weight. This was within the maximum load of 450 short tons (410 t) specified in the design of the bridge.^[k] The figure was a conservative estimate. The cables and guy-wires could support 7,300 short tons (6,600 t), and travel journalist Alfred J. Pairpoint commented that it was normal to see 1,200-short-ton (1,100 t) trains pass over the bridge without danger. Although having no ill effects on its integrity, the bridge shakes whenever a train crosses it. 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 cross over the bridge safely every day.

Through the bridge's lower deck entrance, which is flanked by a toll booth, the deep trusses that help reinforce the bridge's rigidity are visible.

American engineers regard the Suspension Bridge as a major achievement of efficiency. In a fledgling country where resources—material and financial—were limited, they had to make do with whatever was available. This goal was espoused by the American Society of Civil Engineers who stated, "That is the best engineering, not which makes the most splendid, or even the most perfect work, but that which makes a work that answers the purpose well, at the least cost." Roebling had built a bridge that rivaled grander bridges of leading European nations at a much lower cost. His Suspension Bridge used only one-sixth the material of Stephenson's Brittania Bridge, but was twice as long and had a capacity exceeding the tubular bridge. A tubular bridge of equivalent length and load bearing capability would have cost $4 million, whereas the expenditure on Roebling's Suspension Bridge was $400,000. Roebling's success established him as the master of suspension bridges. The inclined guy-wires stretching from the top of towers to the roadway of the Suspension Bridge became the signature of his future works.

Although the Suspension Bridge proved that the suspension system could be safely used to carry railroads, no more suspension railway bridges were built. The outbreak of the American Civil War diverted attention from such civil engineering ventures, and by the time attention was paid to building bridges again, cantilever bridges were in vogue for railway bridges. Regardless, the Suspension Bridge's success made it a model for suspension railway bridges. When the city of Quebec called for a structure to span the St. Lawrence River in 1850, it looked to the Suspension Bridge for inspiration. Seventeen years later the British journal Engineering called for a suspension railway to bridge the Straits of Messina and also referred to Roebling's bridge. Lastly, Stuart used the bridge to introduce the history of American engineering in his 1871 work, Lives and Works of Civil and Military Engineering in America.

Legacy

As a border crossing between two large growing countries, the Suspension Bridge experienced a large throng of travelers. Furthermore, it was the intersection of three major railroads. Coupled with its vicinity to a natural wonder, the Niagara Falls, the bridge brought a lot of railroad traffic into the region once it was opened. The towns at the ends of the bridge benefited greatly from this heavy movement of people and goods. The village of Suspension Bridge, United States, grew quickly in the few years since the opening of the bridge, acquiring shops, factories, and a hotel. Its tourism and commerce soon rivaled the town of Niagara Falls, New York; eventually, the village was merged into the town in 1892. Similarly Clifton on the Canadian end of the bridge was integrated by the town of Niagara Falls, Ontario.

Advertisement for Great Western Railway travel via the Niagara Falls Suspension Bridge, c. 1876.

The bridge's depiction as an engineering marvel and beautiful sight lured many visitors to the Falls. Travelers could, while crossing the bridge, enjoy a view of the Falls enhanced by the sensation of standing 250 feet (76 m) in the air. The Falls, however, proved distant and indistinct to some when there was overcast weather. On the whole, the Suspension Bridge was considered a "must see" for visitors to Niagara Falls. In paintings and prints of the bridge, the Suspension Bridge became the focus, pushing the Falls into the background. Unlike paintings of the Falls that capture the viewer's eye with their majestic views of the natural wonder, pictures of the bridge impressed viewers with the utilitarian design of the structure. By 1897, the inbound trains to Niagara Falls brought 276,900 visitors during the months of May to August. A streetcar system was established in 1882 to handle the growing number of people crossing the bridge. Initially pulled by horses, the trolleys were converted to run on electricity in 1892. The Suspension Bridge was the pride and symbol of the Great Western Railway, who touted it as the "only way route via Niagara Falls & Suspension Bridge".^[l]

Besides boosting local tourism, the opening of the Niagara Suspension Bridge led to an influx of trade in the area. The cities of Niagara Falls boasted commerce that surpassed neighboring settlements. Around the time of its official opening, the bridge was one of the busiest points of trade on the United States-Canadian border, handling $12 million of transitory goods and $2 million of bonded materials into Canada. Due to the large amount of good exchanging hands across the border, the Lewiston customs house handling border trade was relocated to the Niagara Falls Suspension Bridge in 1855. The amount of commerce passing across the bridge made a job at the customs house lucrative, atttracting many men who at times carried out their jobs with zeal. In January 1864, the customs confiscated a shipment of 211 hogs about to cross the bridge into Canada. The United States government had passed a bill that considered livestock as munitions of war and prohibited them from export.

Daredevils, such as Maria Spelterini who was the only woman to cross the Niagara gorge on a tightrope, performed their stunts to crowds on the shore and the Suspension Bridge.

Travelers on the Suspension Bridge bore witness to several death-defying stunts performed across the Niagara Gorge. On June 30, 1859, they saw Charles Blondin's feat of becoming the first man to cross the chasm on a tightrope. In mid-crossing Blondin sat down on the rope and lowered a line to retrieve a drink from the deck of the Maid of the Mist below. In his later tightrope acts at the same spot, the acrobat would perform a different stunt on each occasion. One time he cooked and ate an omelette in mid-crossing, another time he carried his manager Harry Colcord on his back. While giving Colcord a piggyback ride, Blondin stopped five times on the tightrope to rest and recover his strength; each time Colcord gingerly got off Blondin's back and stood on the tightrope, climbing back on after the acrobat had enough rest. His success inspired other acrobats, such as William Leonard Hunt ("The Great Farini"), Samuel Dixon, Clifford Calverly, and Signorina Maria Spelterini, to emulate and try to surpass his acts at the same spot. The Signorina, the only woman to walk across the Niagara on a tightrope, once crossed while blindfolded and another time with her hands and legs in manacles.

Although they did not face the dangers the tightrope walkers, a group of people had their own risks as they fled over the Suspension Bridge, crossing from the United States into Canada. They were the African-Americans forced into slavery and sought freedom by escaping to a country that declared the liberation of any slave who enters it. The bridge was part of the Underground Railroad, a network of routes taken to smuggle slaves in the United States to freedom in Canada. Before the American Civil War the fleeing slaves had only four main routes to get into Canada, of which one was crossing the Niagara River. Slaves who escaped along the Niagara route had help coming from several quarters. The state of New York generally favored the granting of freedom to the country's slaves; this attitude emboldened African-American workers in Niagara to frequently help slaves flee to Canada. Before the Suspension Bridge was completed, the fugitives had to cross the raging river either on board a boat or risk their lives by swimming at calmer points of the river. The Suspension Bridge made the escape across the river easier and safer, although there was still risk. To avoid getting caught and sent back to their owners, slaves had to sneak across on foot or hide aboard trains and oxcarts. Anti-slave activist Harriet Tubman guided the fugitives through the night and bribed custom officials to turn a blind eye. As a result many slaves crossed the Suspension Bridge to freedom before the United States was engulfed in civil war.

When the war ended and the United States turned its focus toward rebuilding itself, Roebling started building his Great Bridge. As the monumental task could affect naval navigation, it required state approval, and the government wanted a thorough review of the engineer's credentials; hence, a Bridge Party was organized. Comprising Roebling and his son, their fellow bridge engineers, generals, businessmen, and high society figures, the party would tour the country and review four bridges Roebling had built before the civil war. The final item on their itinerary was Roebling's Niagara Suspension Bridge. At the dinner to commemorate the end of the bridge tour, civil war veteran General Henry Warner Slocum gave a toast and called the Suspension Bridge a symbol of inspiration for the United States in its rebuilding efforts. This sentiment was shared by the guests and was expressed at several later dinners across the United States. The achievement of building a large suspension bridge over a gorge in the face of overwhelming adversity—constant put-downs by the professional community, American and European—gave the United States a sense of pride. Nationalism rose as the country lauded over the bridge. With lesser technical accomplishments than Europe, the completion of the bridge that had been deemed impossible by the Western world gave the Americans a trophy that stood above any others. The Suspension Bridge became the American symbol to brave the toughest of challenges and do the impossible, pushing their drive for industrialization even harder. Charles W. Woodman specifically drew attention to the Suspension Bridge in his 1865 address to the United States Senate for approval to build a rail system to transport a ship out of the water and up around the Niagara Falls.

Maintenance and replacement

The Suspension Bridge in 1886, after its wooden components had been replaced with steel

Budget concerns forced Roebling to build the Suspension Bridge primarily with wood; the cost of casting the components out of iron and transporting them "[way] out West" was exorbitant. The organic material decayed with time, becoming rotten from the moisture present in the region around Niagara Falls. As the industrialization of United States moved forward at a rapid pace, the introduction of the Bessemer process greatly lowered the cost of the more durable steel and iron. By 1880, the Suspension Bridge's wooden trusses, beams, and flooring were replaced with steel versions. The wire cables were not replaced, their cores were still in pristine condition. The outer layer of wires in the cables were, however, lightly corroded and had to be replaced. Due to severe deterioration, the limestone towers were replaced in 1886 with steel framed versions.

The weight of trains in North America has greatly increased by the mid-1890s. Larger and more powerful locomotives were required to pull cars that were handling an increasing number of passengers and demand for goods; compared to the 23-short-ton (21 t) locomotives making their way across the bridge in the 1850s, 170-short-ton (150 t) locomotives were the common engines 40 years later. The weight of these trains exceeded the specifications of the Suspension Bridge, and the bridge companies took the opportunity to review and request for the replacement of the bridge. Civil engineer Leffert L. Buck, who had been hired to maintain the Suspension Bridge, was tasked to design the replacement bridge. He settled for a bridge of the arch design. At that time, arch bridges were the new models for railway bridges and were more cost-efficient than suspension bridges. Buck built the new bridge around and below the Suspension Bridge, replacing it piece by piece at a time. His plan allowed bridge traffic—train and pedestrian—to continue without disruption. By August 27, 1897, the last pieces of the Suspension Bridge was dismantled, leaving the Lower Steel Arch Bridge—later renamed the Whirlpool Rapids Bridge—in its stead. On inspection the core of the cables formerly holding up the Suspension Bridge were found to be still as good as the day the bridge was built.

Footnotes

a. ^{^} Merritt was not alone in dreaming of a suspension bridge across the Niagara. Engineers Francis Hall, Charles Ellet, Jr., and Charles B. Stuart had individually spoke about such an idea in the years before the Suspension Bridge was started.

b. ^{^} The Horseshoe Falls have receded 3–6 feet (0.9–1.8 metres) per year before the 1950s and are receding at a rate of 1–2 feet (0.3–0.6 metres) per year thereafter. Due to this erosion, it may no longer be visible from the location stated in the article.

c. ^{^} Stuart and Merritt, at this time, were leading the joint ventures that formed the bridge companies.

d. ^{^} The prize money was stated to be $5 or $10 among various sources. This article follows the McCullough source.

e. ^{^} Similarly, Homan Walsh was either a 10-year-old or 15-year-old boy depending on the source. This article follows the Robinson source.

f. ^{^} Although Robinson stated the "toll" as $1.25, this article follows the $1.00 fee stated by Crabtree and Tyrell.

g. ^{^} A railway bridge with a double-deck design was suggested by civil engineer Squire Whipple during the early planning stage of the project.

h. ^{^} Sir Samuel Brown's Stockton Railway Bridge in the United Kingdom was the first suspension bridge designed to carry railway traffic, but it could not support the weight of a locomotive. Hence, it was non-operational as a railway bridge. Built in 1829, the bridge was closed in 1830.

i. ^{^} A similar design, proposed by engineer John Trautwine, was exhibited 18 months before the construction of the Suspension Bridge. It was not used in any suspension bridges.

j. ^{^} Serrell's Lewiston Suspension Bridge collapsed in 1864, and Keefer's Falls View Suspension Bridge in 1889.

k. ^{^} The difference between "Weight of superstructure" and "Weight of superstructure and maximum loads".

l. ^{^} As pictured in the advertisement for the Great Western Railway shown in this article.

Bibliography

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External links

• Bridges Over Niagara Falls at Niagara Falls Thunder Alley
• Niagara Falls Bridge (1855) at Structurae