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25-586: The Lyman Viaduct is a buried railroad trestle built over Dickinson Creek in Colchester, Connecticut , in 1873. Along with the nearby Rapallo Viaduct , it is one of the few surviving wrought iron railroad trestles from the first generation of such structures. It was built for the Boston and New York Air-Line Railroad , whose successor, the New York, New Haven and Hartford Railroad (NYNH&H), buried it in

50-417: A river or other bodies of water . Flood channels are sometimes built on the former courses of natural waterways as a way to reduce flooding. Channelization of this sort was commonly done in the 1960s, but is now often being undone, with "rechannelization" through meandering, vegetated, porous paths. This is because channellizing the flow in a concrete chute often made flooding worse. Water levels during

75-401: A flood tend to rise, then fall, exponentially. The peak flood level occurs as a very steep, short spike; a quick spurt of water. Anything that slows the surface runoff (marshes, meanders, vegetation, porous materials, turbulent flow, the river spreading over a floodplain) will slow some of the flow more than other parts, spreading the flow over time and blunting the spike. Even slightly blunting

100-485: A trestle from which to dump the fill. Timber trestles remain common in some applications, most notably for bridge approaches crossing floodways , where earth fill would dangerously obstruct floodwater. For the purposes of discharging material below, a coal trestle carried a dead-end track, rather than a bridge. One of the longest trestle spans created was for railroad traffic crossing the Great Salt Lake on

125-675: A wooden trestle. Being less susceptible to fire damage in this brushy location is also an advantage. The approaches to the Kate Shelley High Bridge near Boone, Iowa, are steel trestles. New Orleans utilizes steel trestles to support parts of I-10 , the Pontchartrain Expressway , and Tulane Avenue . Also, trestles support the elevated railroad leading to and from the Huey P. Long Bridge . The first major prestressed concrete trestle railroad bridge built

150-435: Is also resilient to the stresses imposed. The structure also naturally leads to a certain redundancy (provided that economic considerations are not overly dominant). Such wooden coasters, while limited in their path (not supporting loops), possess a certain ride character (owing to structural response) that is appreciated by fans of the type. The Camas Prairie Railroad in northern Idaho utilized many timber trestles across

175-573: The Kinzua Bridge in Pennsylvania , later rebuilt in steel. Because records of its construction are incomplete, forensic analysis of the structure (for example, by excavating a portion of the embankment) is expected to provide significant information about its design and construction, in particular how its construction may have deviated from known plans. Trestle bridge Timber and iron trestles (i.e. bridges) were extensively used in

200-512: The Lucin Cutoff in Utah . It was replaced by a fill causeway in the 1960s, and is now being salvaged for its timber. Many wooden roller coasters are built using designs similar to trestle bridges because such a structure can be strong and support a high track path while using a relatively small amount of material. Since loads are well distributed through large portions of the structure it

225-429: The 19th century, the former making up from 1 to 3 percent of the total length of the average railroad. In the 21st century, steel and sometimes concrete trestles are commonly used to bridge particularly deep valleys, while timber trestles remain common in certain areas. Many timber trestles were built in the 19th and early 20th centuries with the expectation that they would be temporary. Timber trestles were used to get

250-792: The Kansas City Southern Railroad. The trestles were completed in 1936, after construction of the Spillway. The trestles may be the longest wooden railroad trestles remaining in regular use in North America. A coal trestle is a rigid-frame trestle supporting train tracks above chutes, used to deliver fuel to boats or trains beneath it. At the top of the trestle, rolling stock (typically hopper cars ) open doors on their undersides or on their sides to discharge cargo. Coal trestles were also used to transfer coal from mining railroads to rail cars. They were prominent when coal

275-526: The developing railway network in the United Kingdom. These generally carried decking consisting of some form of trussed girder, as at Crumlin Viaduct, Belah and Meldon ; though two rare examples, at Dowery Dell (demolished in 1962), and Bennerley had lattice girder decks. The steel trestle at Martinez, California, shown below, is a modern structure with a long expected lifetime compared to

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300-454: The floodwaters go down. Flood control channels are not to be confused with watercourses which are simply confined between levees . These structures may be made entirely of concrete , with concrete sides and an exposed bottom, with riprap sides and an exposed bottom, or completely unlined. They often contain grade control sills or weirs to prevent erosion and maintain a level streambed. By definition, flood control channels range from

325-578: The many deep valleys in Cornwall on the spinal rail route through the county. These were all replaced by masonry viaducts. Few timber trestles survived into the 20th century. Two that did, and which are still in daily use, cross the Afon Mawddach on the coast of Wales only a few miles apart, at Barmouth and Penmaenpool . The former, built in 1867, carries trains on the heavy rail Cambrian Coast Line travelling from England via Shrewsbury to

350-576: The multiuse Air Line Trail by the state. This trestle and the nearby Rapallo Viaduct , which was similarly buried, were among the world's first examples of wrought iron railroad trestles, and are the only known ones of that period that are believed to be in good condition, due to their entombment. The only earlier known examples of this technology include the Verrugas Bridge in Peru , begun before these, completed in 1873, and washed away in 1889, and

375-420: The railroad to its destination. Once the railroad was running, it was used to transport the material to replace trestles with more permanent works, transporting and dumping fill around some trestles and transporting stone or steel to replace others with more permanent bridges. In the later 20th century, tools such as the earthmover made it cheaper to construct a high fill directly instead of first constructing

400-637: The rolling Camas Prairie and in the major grade, Lapwai Canyon. The 1,490-foot (450 m) viaduct across Lawyers Canyon was the exception, constructed of steel and 287 feet (87 m) in height. The floodway of the Bonnet Carré Spillway in St. Charles Parish, Louisiana, is crossed by three wooden trestles each over 1.5 miles (2.4 km) in length. The trestles are owned by the Canadian National Railway (two trestles) and

425-515: The sand rather than replacing it with a stronger structure. The viaduct was added to the National Register of Historic Places in 1986 since it is capable of providing detailed information about construction methods of the period. The viaduct now carries the multi-use Air Line State Park Trail . The Lyman Viaduct is located in a rural setting of northwestern Colchester. Its center is about 0.5 miles (0.80 km) west of Bull Hill Road on

450-541: The size of a street gutter to a few hundred or even a few thousand feet wide in some rare cases. Flood control channels are found in most heavily developed areas in the world. One city with many of these channels is Los Angeles , as they became mandatory with the passage of the Flood Control Act of 1941 passed in the wake of the Los Angeles Flood of 1938 . This engineering-related article

475-412: The spike significantly decreases the peak flood level. Generally, the higher the peak flood level, the more flood damage is done. Straight, clear, smooth concrete-walled channels speed up flow, and are therefore likely to make flooding downstream worse. Modern flood control seeks to "slow the flow", and deliberately flood some low-lying areas, ideally vegetated, to act as sponges, letting them drain again as

500-403: The state-maintained Air Line Trail. It is a wrought iron post deck truss design, 1,112 feet (339 m) long with a maximum height of 137 feet (42 m). The structure consists of bents formed out of three quarter-round rolled wrought iron sections, with flanges designed to facilitate riveted assembly. At the stream crossing point, there are four 30-foot (9.1 m) columns. Each tier of

525-502: The trestle is joined horizontally and laterally to adjacent members. The entire structure is buried in earthen fill and topped by a dense pack of cinder blocks, now somewhat overgrown on the sides. The viaduct was built in 1873 by the Phoenix Iron Works for the Boston and New York Air-Line Railroad , which aimed to provide service between New York City and Boston, Massachusetts , via Middletown, Connecticut . The viaduct

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550-409: The various small towns on Cardigan Bay . It also carries a toll-path for pedestrians. Road traffic at this location has to travel many miles around the estuary to cross at either (for light traffic) the second trestle bridge, at Penmaenpool, which is a toll bridge; or (for heavy traffic) at Dolgellau even further up the estuary. Trestles in cast- or wrought-iron were used during the 19th century on

575-474: Was an important fuel for rail locomotion and steamships , before they were replaced with mechanical coal loaders during the 20th century. Coal trestles were used in the Great Lakes ports of Buffalo (on Lake Erie ), Sodus Point and Oswego, New York (both on Lake Ontario ). In the United Kingdom, timber trestles were relatively short-lived as a structural type, one of their major uses being to cross

600-460: Was one of the largest single capital expenses of the railroad venture, which was beset by cost overruns and failed after just ten years of operation. Taken over by the NYNH&;H, the viaduct was filled as a comparatively inexpensive means of strengthening the structure for use by heavier equipment in the early 20th century. The line remained in operation into the 1960s, and has since been adapted as

625-471: Was the Atlantic Coast Line's Salkehatchie River trestle. Flood control channel Flood control channels are large and empty basins where surface water can flow through but is not retained (except during flooding ), or dry channels that run below the street levels of some larger cities , so that if a flash flood occurs the excess water can drain out along these channels into

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