By Allan King Sloan
July 2004

Along with his fellow bridge-builders of the last half of the 19th century, Zenas King was far sighted enough to accommodate the need for movable bridges. The rapid pace of industrial growth made it essential to find a way to bridge active rivers and canals used by a variety of watercraft of different sizes so that road and railroad traffic could traverse without permanently interfering with the flow of either type of traffic. This was a particular problem in the fast-expanding cities with important navigable watercourses and movable bridges were the answer.

Soon after Zenas King began producing his patented tubular arch bowstring bridge in volume, he sought and obtained a second patent for a tubular swing bridge in 1864. He had been building bridges mounted on turntables before receiving his patent, but once his designs were patented, he and his agents began to sell these bridges all over the country. Three of the strongest markets for these moveable bridges were Cleveland, Chicago, and New York City, but there were also successful sales made in New England, Michigan, New Jersey and as far away as Oakland, California. Turntable swing bridges were a prominent feature of the King Bridge Company’s catalogues through the 1890s, along with retractile and lift bridges.

By the beginning of the 20th century, however, turntable bridges had lost favor and bascule and high lift structures became the norm. By teaming with William Scherzer, the designer of a very successful bascule bridge, the company was able to continue building movable bridges in this new era. At least one of its bascules still in active use, Old Nan, a 1905 Scherzer bascule across the Niantic River in Connecticut still carries Amtrak trains speeding between Boston and New York City.

Most of the King-built movable bridges have long since disappeared. However, there are a few still standing as of the beginning of 2004 and two still in full operation, the Center Street Bridge in Cleveland, and Old Nan. Others, like the St. Francisville, Illinois, Bridge are in use for traffic but without their moveable sections in operation. Still others are fully retired as active traffic carriers and used as technology exhibits or pedestrian crossings, like the B&O Scherzer Bridge in Cleveland, the “New Bridge” in River Edge, New Jersey, and the lift bridge in Piermont, New York. The University Heights Bridge in New York City started life as the Harlem Ship Canal Bridge and was moved and completely rebuilt, retaining only the design and the sidewalk railings. It is still in use. And the last of the King built railroad swing bridges, the Hojack Bridge in Rochester, still sits in the middle of the Genesee River awaiting its fate.


The problem of bridging the twisting Cuyahoga River as it meandered through Cleveland’s prime water-related industrial area known as “the Flats”, gave Zenas his earliest opportunity to sell his new movable bridges. In 1864, just five years after he started in the business, he won a contract to build a 180-foot turntable bridge of tubular wrought-iron boilerplate at Columbus Street in the Flats. The following year he built a similar structure at Senaca Street and in 1871 a third bridge using his patented design at Jefferson Street.[1] When open, cable stays were used to support the plate girders. The city engineers were very happy with this type of well-balanced bridge for it could easily be opened and closed by a single operator using hand power and thus keep both river and road traffic flowing smoothly with a minimum of disruption.

Later on in the 1880’s, two additional turntable bridges across the Cuyahoga River were listed in the King Bridge Company catalogues; the first, a 200-foot truss swing at Main Street with an 18-foot roadway and 9-foot sidewalks, the second, a bridge built for the Valley Railway Company consisting of a 170-foot swing span and a 32-foot plate girder. However, as both river and road and rail traffic increased, this type swing bridge built with a large pier in the middle of the river to support the turntable and its power mechanisms, became less desirable. New bridge building techniques, including bascules and vertical lifts, plus the construction of high level viaducts across the valley eliminated this navigation obstacle and made the turntable bridges obsolete. Most of these early King swings were replaced using this improved technology.

In keeping up with the times and new technology, the King Bridge Company was able to continue providing crossings of the Cuyahoga after the original swings become obsolete. The Central Viaduct, built by the company in 1889, was the second high level crossing of the valley. It was originally built with a swing span across the river, constructed by cantilevering two arms from the central pier without the use of falsework that would have blocked river traffic. This section was later replaced after a speeding trolley car plunged into the river before the swing span was closed.

In 1901, the company built the Center Street swing bridge, which had its turntable structure located on the north bank of the river with a long arm reaching across the water and a shorter arm connecting to the roadway rather than on a pier in the center of the river. This design made it easier to preserve the bridge, which in addition to being the last swing bridge on the Cuyahoga, is also among the bridges cited in Eric DeLony’s Landmark American Bridges, and is listed on the National Register of Historic Places. It is a civic monument that is still used to move traffic and is a favorite bridge of the chief bridge engineer of the City of Cleveland’s Division of Engineering and Construction who is responsible for its maintenance.


[Photo Courtesy of William Vermes]

In 1907, the Company constructed the 230-foot bascule bridge on Whiskey Island at the north end of the Cuyahoga River for the Baltimore and Ohio Railroad, in collaboration with the Scherzer Engineering Company of Chicago. It was the longest bridge of the Scherzer design built at the time and was one of a number of Scherzer bridges built for the railroads to cross the Cuyahoga. It is one of two remaining bridges built as a result of the Scherzer-King collaboration. The other is the Old Nan Railroad Bridge, also built in 1907, across the Niantic River in Connecticut. (see below)

Along with the Center Street swing bridge, the B&O bascule bridge, although not in use, still stands as a proud part of Cleveland’s bridge engineering heritage and is prominently displayed in the city’s remarkable inventory of historic bridges. The bridges of the Cuyahoga are illuminated at night to provide a sparkling tableau to the city’s skyline, a leftover from Cleveland’s 200th birthday celebration in 1996.


Zenas King apparently had strong connections to Chicago, the rival of Cleveland for industrial supremacy on the Great Lakes in the last half of the 19th century. It was the headquarters for the infamous “bridge trust” set up in 1883 by Zenas and sixteen of his fellow bridge builders, including the Wrought Iron Bridge Company of Canton and American Bridge of Chicago, to manage the fierce competition in the industry by arranging “pools” to control costs and territory.[2] When in town, evidently Zenas and his salesmen were able to convince the city engineers of Chicago that they could provide good economical swing bridges to link the fast developing city center on the east side of the Chicago River with the vast hinterland on the west. The company catalogues of the late 1880s and 1890s showed prominently three important swing bridges crossing the river, at Adams Street, at 12th Street, and at 18th Street.

The Adams Street Bridge consisted of three spans, the 259-foot middle swing span of which was built by the company (and perhaps the stationary spans as well). This was a bridge with two 21-foot roadways and eight-foot sidewalks on each side on one of the main entry points to the downtown. It lasted until1923. The 12th Street Bridge was a structure of three 114-foot spans. It had two 20-foot roadways and six-foot sidewalks on each side. The 18th Street Bridge was 173 feet long but with only one 21-foot roadway two seven-foot sidewalks. The company’s workers responsible for the decorative ironwork must have been very happy with these projects, for the three bridges contained a plethora of fine decorative elements including imaginative lacework, finials, and prominently displayed builder’s plates.

Eventually, the growth of both river and road traffic made it hard for swing bridges built on a central river pier to prevent traffic jams and river accidents. City engineers found a better solution in the bascule bridges that could be built and operated without permanently blocking the river. As a result, the City of Chicago developed a program to replace the turntable bridges with the standard bascule bridges that one sees crossing the Chicago waterways today. While most of these bascules have no overhead structure to catch the eye as did the old turntable bridges, they make it possible to cross the river with little notice. It is only when one is in a boat touring the river that the design of the bridges is apparent.

One other King swing bridge built in the Chicago area was pictured in the 1890s company catalogues, a double track railroad span of 210 feet across the Calumet River in South Chicago. It was constructed for the ILL, L.S. & M.S. R.R. to serve the steel mills and was still in operation in the 1960s. Its fate since then is not known, but its design was replicated in the Hojack Swing Bridge that is still standing in the Genesee River in Rochester, New York (see below).


In an old King family photo album, there is a remarkably clear picture of a high truss bowstring bridge mounted on a large turntable in Manistee, Michigan on the eastern shore of Lake Michigan. While there is no reference to this bridge in the company catalogues, it is probably one of the earliest of the movable bridges built by the company combining the designs of the two bridge patents Zenas secured in the 1860s. The Company was an active participant in the bridge-building boom in the states bordering its Ohio home, particularly for the railroads. Two of these are of particular note.

Click on this link to see the Portage Lake Bridge.

The first was the old Portage Lake Bridge, a six-span two-deck combination railroad and highway bridge with a movable center section built in 1895 across Portage Lake between Houghton and Hancock in Michigan’s upper peninsula. The bridge was designed by the Osborn Engineering Company of Cleveland, the firm founded by Frank Osborn, former chief engineer of the King Bridge Company. It was used extensively for both road vehicles and the Copper Range Railroad trains until 1959 when it was replaced by a larger and wider lift bridge built by the American Bridge Company, a former rival and sometimes partner of King. This bridge is well documented in photos in the archives of Michigan Technical University.

The second bridge has a most remarkable history. It crosses the Wabash River between Illinois and Indiana at St. Francisville, Illinois, which once carried the famous Wabash Cannonball train. The story has it that this bridge was originally constructed by the King Bridge Company in Wilmington, Delaware, in 1897, then bought by the railroad, dismantled, and moved to its present site in 1906. It served until the rail line was abandoned, at which time it was purchased by a local farmer who used it to move his produce across the river. He operated the bridge as a toll facility for cars. It is a narrow bridge that can be used for one-way traffic only and has a center span built on a movable turntable. It is still being used today operated and maintained jointly by the City of St. Francisville and the Illinois Highway Department and is considered to be an important historical asset.

St. Francisville Bridge, A/k/a Wabash Cannonball Bridge in Illinois

Photo Courtesy of Paul Kennedy.


New York City has more storied long-span bridges than any other city in the world from the Brooklyn Bridge and its companions across the East River, the Manhattan, Williamsburg, and Queensboro Bridges, to the Triboro, Hells Gate, Whitestone, and Throggs Neck Bridges across Long Island Sound, and the George Washington and Verrazano, Bayonne, Goethels and Outerbridge Crossing Bridges connecting across the Hudson, the Harbor and Kill Van Kull to New Jersey. However it also has a number of less dramatic bridges crossing the narrower waterways like the Harlem River and the canals of Brooklyn and Queens that are essential parts of the city’s street system. It was in this latter category that the King Bridge Company made its contribution to the city’s transportation system in the late 19th century by building movable bridges. After the Civil War, the company opened an office at 18 Broadway near Wall Street manned by an agent, name unknown, who must have been quite active.

As early as 1874, the King Bridge Company was selected to build the Grand Street Bridge in Eastern Brooklyn across Newtown Creek. This was a drawbridge built for $18,200 and was in service for fifteen years but suffered from poor maintenance. The company bid on its replacement in 1888 but lost out to a local contractor. However, the company did display one of its New York moveable bridges in its catalogues of the 1880s. This was a 168-foot wrought iron high-truss swing bridge on Manhattan Avenue in the Greenport section of Brooklyn. This bridge also has long since disappeared.

In the 1890s company catalogues, there are two notable swing bridges pictured across the Harlem River: first a three-span bridge with a center movable span of 268 feet across the Harlem Ship Canal at Knightsbridge Road; and the second, a four-track swing bridge built for the New York Central and Harlem River Railroad. Both were built in 1895. The railroad bridge had two fixed spans of 185 and 134 feet respectively and a central swing span of 389 feet mounted on a massive double drum turntable. It had replaced a 1860s fixed span bridge and was replaced in turn in 1954 by a lift bridge still operating today on one of the nation’s most important rail lines.[3]

The Knightsbridge Road swing bridge (also called the Harlem River Ship Canal Bridge) had a most interesting history. It was originally built between 1893 and 1895 when the narrow Spuyten Duyval Creek was being converted into the Harlem Ship Canal to connect the Hudson and Harlem Rivers. The noted journal Harper’s Weekly ran an article about the building of the Harlem Ship Canal with an engraving showing the swing bridge with its steam powered turntable carrying pedestrians and carriages across the water. However, by 1905, as the City was expanding by building its network of subway lines to connect the boroughs, the bridge needed replacement in order to carry the IRT Broadway line into the Bronx. To save money, the central swing and adjacent spans were lifted from their piers, floated by pontoon scow, and placed onto new piers and abutments at 207th Street, about a mile down river from the original site to replace an earlier bridge. There it served as the University Heights Bridge for most of the 20th century. Because of its handsome profile and ornamental ironwork, the City Department of Transportation decided to replicate the design of the bridge when it was reconstructed and widened in the 1990s, keeping only the iron sidewalk railings from the original bridge.

The records and bridge literature of New York City credits the design of the original ship canal bridge to three noted engineers and bridge designers, William Burr, consulting engineer to the City Department of Public Works, George Birdsall, chief engineer of the department, and Alfred P. Boller, the designer of this and other movable Harlem River bridges. The contractor for the bridge was listed as A. McMullen & Co., a company not listed among the major bridge builders of the time[4]. It could be that McMullen was acting as agent for a number of sub-contractors hired to build the bridge including the King Bridge Company. As yet no mention has been found of the King Bridge Company as the builder of the original structure, but the search is on-going.

The King Bridge Company did received credit as the builder of at least one other movable bridge in New York City, the 123- foot retracticle bridge constructed in 1893 to carry pedestrians, wagons and trolleys across the Wallabout Canal at Washington Street in Brooklyn. While this bridge was not featured in the Company catalogues, the L (Summer) Street Bridge in South Boston, a retractile bridge of similar design, was pictured and it was in service for over 100 years, replaced only in 2002. (See below)

There are two other King-built moveable bridge still standing in the Metropolitan New York Region. The first is the Old “New Bridge” crossing the Hackensack River in River Edge, New Jersey, not far from the George Washington Bridge, at the site of the Steuben House historical center. This is a Pratt low-truss swing bridge built by the company in 1889 using channel iron furnished by its sometimes rival, the Phoenix Bridge Company of Pennsylvania. It is the oldest such structure in New Jersey and has recently been refurbished by Bergen County. It is listed on the National Register of Historic Places. The second is farther north in Rockland County, New York, at Piermont on the Hudson River. This is a small lift bridge across a narrow canal that once was used for barge traffic. It was built in 1890 and is used now only for bicycle and pedestrian traffic, but it still has its superstructure and lifting mechanism in tact, along with a prominently displayed builder’s plate.


Despite the fact that Zenas King’s first employer, the Cincinnati bridge builder William Moseley, had moved his operations to New England soon after Zenas began his own operations in Cleveland, the King Bridge Company also began expanding their sales operations into Moseley’s new turf. The company had set up a sales office in Boston under the direction of Mr. N. Cowdrey and began soliciting business all over the region with some success. Maine was a particularly good market for the company’s bowstrings and standard trusses. It was in Massachusetts that the movable bridges were mainly sold.

In 1892, the year of Zenas’s death, the company built a 127-foot retractile bridge on L (Summer) Street across the Reserve Channel in South Boston, one of a number of retractile and turntable bridges built to cross the waterways leading into Boston Harbor. This bridge was the principal retractile bridge featured in the company catalogues of the 1890s. It served for over a century and was only dismantled in 2002 as part of the improvements in the local street system generated by the “Big Dig” project. Because there were other old movable bridges in South Boston of a similar design, this bridge was considered expendable. Our family was able to salvage one of the two builders plates prominently featured on the crossbeam.

In 1897, the company was contracted to build a turntable swing bridge across the Danvers River between Beverly and Salem to replace an earlier structure. This was a 122- foot, rim-earing Warren pony truss that was designed to carry street cars as well as other surface vehicles. Known as the Essex Bridge, it was one of the oldest of the sate’s movable bridges and was extensively repaired over the years until it was replaced in 1997 by a long span structure after a long period of agitation by the local community.[5]

One of the most remarkable of the King movable bridges is “Old Nan” across the Niantic River between Niantic and Waterford, Connecticut. It is the oldest of five movable bridges still operating on the rail line between Boston and New York and used daily by Amtrak’s Acela high-speed trains. It consists of four fixed-deck girder spans plus a 69 foot center span which is a Scherzer bascule. The bridge was built in 1907 and has been in continuous operation ever since. It has been documented in the Historic American Engineering Record, archived in the Library of Congress, and still has both the builder’s plates of the King Bridge Company and the Scherzer Rolling Lift Bridge Company. With the desire of Amtrak to increase the operation of high-speed trains up to at least 35 per day, the prospect of keeping this bridge in operation is limited. While in the winter it is seldom opened to let boats through, in the summer there is a considerable amount of boat traffic in and out of the river requiring quite a bit of movement from the old gears and engines that need constant maintenance. Replacement solutions are still being studied and most will require removing the old bridge, which while not very elegant in appearance, represents a living example of a fine old engineering technology.


Two other moveable bridges were described in the King Bridge Company catalogues of the 1890s. One is in Dayton, Ohio, on Second Street over the Miami and Erie Canal. It was an unusual forty-five foot lift bridge with two eight foot walkways that appeared to have been moved up and down by some sort of hydraulic device. The other is a more familiar type turntable bridge over the tidal canal in Oakland, California. It had a draw span of 315 feet and two approach spans of thirty-three feet each with a roadway width of twenty-five feet. It had a profile similar to the University Heights Bridge in New York City, the Calumet River Bridge in South Chicago, and the center span of the Portage Lake Bridge in upper Michigan.


While there may be some remaining King-built movable bridges that we do not know about, there is one still standing that is the sibling of the University Heights, Calumet River, and Portage Lake turntable bridges described above. It is the Hojack Railroad Bridge built by the King Bridge Company in 1905 for the New York Central Railroad near the mouth of the Genesee River in Rochester, New York. It was last used in 1993 and now stands majestically in the middle of the river awaiting its fate. The U.S. Coast Guard has ordered its current owner, Conrail, to remove it, but has held off enforcing the order to allow a local group to study its future use as a part of a revived trolley car system designed to tie together some of the recreational and cultural amenities of the region and become a tourist attraction. Despite the reluctance of the city fathers of Rochester to support saving the bridge, there has been a valiant group of local citizens actively campaigning for its retention and reuse, the Society for Industrial Archeology and other historic preservation interests have been lending support to saving one of the last of this breed of railroad swing bridges. Stay tuned.

Photo courtesy of Richard Margolis. Please see the “Hojack Special” section of this website for important updated information

[1] See “Bridging the Flats: Navigating the Streets and Railroads of Cleveland” by David Simmons in the Proceedings of the 7th Historic Bridges Conference, 2001, published by the Watson Bridge Book Collection of Cleveland State University, pp 146 ff.

[2] See “Bridge Building on a National Scale: The King Iron Bridge and Manufacturing Company” by David A. Simmons in IA the Journal of the Society for Industrial Archeology, Volume 15, Number 2, 1989, pp23 ff.

[3] See The Bridges of New York by Sharon Reier, Dover Publications Inc., Mineola, New York , 1977, pp 82-83.

[4] See The Directory of American Bridge Building Companies 1840-1900 by Victor C.Darnell, published by the Society of Industrial Archeology 1984.

[5] Ironically, one of my first professional assignments when I began working in the Boston region was to direct a program to involve local citizens in the transportation planning process called the Boston Transportation Planning review. Our first assignment was to hear the arguments from residents of Beverly and Salem for replacing the bridge. At the time, in 1972, I was not aware that the bridge was built by my great grandfather’s company. Had I known, I might have had a conflict of interest.


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