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82-585: The Tuatapere Branch , including the Orawia Branch , was a branch line railway in Southland , New Zealand . Although the Tuatapere and Orawia Branches look like a single line, operationally they were considered separate lines. The first section opened to Riverton in 1879 and reached Tuatapere three decades later. The extension from Tuatapere to Orawia operated from 1925 until 1970. In 1976

164-470: A Parker truss or Pratt truss than a true arch . In the Brown truss all vertical elements are under tension, with exception of the end posts. This type of truss is particularly suited for timber structures that use iron rods as tension members. See Lenticular truss below. This combines an arch with a truss to form a structure both strong and rigid. Most trusses have the lower chord under tension and

246-428: A spur line . Branch lines may serve one or more industries, or a city or town not located on a main line. Branch lines may also connect two or more main lines. An industrial spur is a type of secondary track used by railroads to allow customers at a location to load and unload railcars without interfering with other railroad operations. Industrial spurs can vary greatly in length and railcar capacity depending on

328-550: A Parker truss vary from near vertical in the center of the span to diagonal near each end, similar to a Warren truss. George H. Pegram , while the chief engineer of Edge Moor Iron Company in Wilmington, Delaware , patented this truss design in 1885. The Pegram truss consists of a Parker type design with the vertical posts leaning towards the center at an angle between 60 and 75°. The variable post angle and constant chord length allowed steel in existing bridges to be recycled into

410-510: A common sight along railroads in industrial and rural cities alike. As automobile and roadway technology improved throughout the early and mid-20th century, most low volume industry spurs were abandoned in favor of the greater flexibility and economic savings of trucking. Today, railroads remain the most economical way to ship large quantities of material, a fact that is reflected in industrial spurs. Most modern day spurs serve very large industries that require hundreds, if not thousands, of carloads

492-599: A common truss design during this time, with their arched top chords. Companies like the Massillon Bridge Company of Massillon, Ohio , and the King Bridge Company of Cleveland , became well-known, as they marketed their designs to cities and townships. The bowstring truss design fell out of favor due to a lack of durability, and gave way to the Pratt truss design, which was stronger. Again,

574-435: A conventional truss into place or by building it in place using a "traveling support". In another method of construction, one outboard half of each balanced truss is built upon temporary falsework. When the outboard halves are completed and anchored the inboard halves may then be constructed and the center section completed as described above. The Fink truss was designed by Albert Fink of Germany in 1854. This type of bridge

656-481: A limited number of truss bridges were built. The truss may carry its roadbed on top, in the middle, or at the bottom of the truss. Bridges with the roadbed at the top or the bottom are the most common as this allows both the top and bottom to be stiffened, forming a box truss . When the roadbed is atop the truss, it is a deck truss; an example of this was the I-35W Mississippi River bridge . When

738-477: A lower chord (functioning as a suspension cable) that curves down and then up to meet at the same end points. Where the arches extend above and below the roadbed, it is called a lenticular pony truss bridge . The Pauli truss bridge is a specific variant of the lenticular truss, but the terms are not interchangeable. One type of lenticular truss consists of arcuate upper compression chords and lower eyebar chain tension links. Brunel 's Royal Albert Bridge over

820-464: A mainline, they tend to have lower maintenance and signaling (train control) standards. Before the rise of the long-distance trucking in the early 1930s, railroads were the primary means of transportation around the world. Industries of the era were commonly built along railroad lines specifically to allow for easy access to shipping. Short (under a mile, oftentimes only several hundred yards) industrial spurs with very small (under ten car) capacities were

902-789: A new span using the Pegram truss design. This design also facilitated reassembly and permitted a bridge to be adjusted to fit different span lengths. There are twelve known remaining Pegram span bridges in the United States with seven in Idaho , two in Kansas , and one each in California , Washington , and Utah . The Pennsylvania (Petit) truss is a variation on the Pratt truss . The Pratt truss includes braced diagonal members in all panels;

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984-459: A pin-jointed structure, one where the only forces on the truss members are tension or compression, not bending. This is used in the teaching of statics, by the building of model bridges from spaghetti . Spaghetti is brittle and although it can carry a modest tension force, it breaks easily if bent. A model spaghetti bridge thus demonstrates the use of a truss structure to produce a usefully strong complete structure from individually weak elements. In

1066-823: A section of the West Rail line . Discontinued services include the Sha Tau Kok Railway and the Wo Hop Shek Branch . A spur line to Siu Sai Wan has been proposed. Delhi On the Delhi Metro , the Blue Line has a Branch Line with 8 Stations, linking Yamuna Bank to Ghaziabad via Anand Vihar ISBT and terminating at Vaishali. The first section of the Branch opened on 8 January 2010 with Anand Vihar as its terminal with six stations. It

1148-531: A subsidy for grain transport, and instead allowed railways to absorb branch line subsidies freely without making effort to improve the profitability of the lines. The term "grain-dependent branch lines" began being used as early as 1978 to refer to the special case of these branch lines in agricultural areas whose viability depended on the economics of grain transport. The Western Grain Transportation Act of 1983 addressed this case specifically, but

1230-545: A variant of the lenticular truss, "with the top chord carefully shaped so that it has a constant force along the entire length of the truss." It is named after Friedrich Augustus von Pauli  [ de ] , whose 1857 railway bridge (the Großhesseloher Brücke  [ de ] ) spanned the Isar near Munich . ( See also Grosshesselohe Isartal station .) The term Pauli truss is not interchangeable with

1312-466: A year. There is an international branch line between Italy and Vatican: the 300-metre Vatican Railway , connecting from the Pisa-Rome railway mainline at Roma San Pietro railway station , to Vatican City station . Many British railway branch lines were closed as a result of the " Beeching cuts " in the 1960s, although some have been re-opened as heritage railways . The smallest branch line that

1394-700: Is a Pratt truss design with a polygonal upper chord. A "camelback" is a subset of the Parker type, where the upper chord consists of exactly five segments. An example of a Parker truss is the Traffic Bridge in Saskatoon , Canada. An example of a camelback truss is the Woolsey Bridge near Woolsey, Arkansas . Designed and patented in 1872 by Reuben Partridge , after local bridge designs proved ineffective against road traffic and heavy rains. It became

1476-519: Is a hybrid between a Warren truss and a double-intersection Pratt truss. Invented in 1863 by Simeon S. Post, it is occasionally referred to as a Post patent truss although he never received a patent for it. The Ponakin Bridge and the Bell Ford Bridge are two examples of this truss. A Pratt truss includes vertical members and diagonals that slope down towards the center, the opposite of

1558-450: Is functionally considered to be a flexible joint as opposed to a rigid joint with the strength to maintain its shape, and the resulting shape and strength of the structure are only maintained by the interlocking of the components. This assumption means that members of the truss (chords, verticals, and diagonals) will act only in tension or compression. A more complex analysis is required where rigid joints impose significant bending loads upon

1640-832: Is named after the K formed in each panel by the vertical member and two oblique members. Examples include the Südbrücke rail bridge over the River Rhine, Mainz, Germany, the bridge on I-895 (Baltimore Harbor Tunnel Thruway) in Baltimore, Maryland, the Long–Allen Bridge in Morgan City, Louisiana (Morgan City Bridge) with three 600-foot-long spans, and the Wax Lake Outlet bridge in Calumet, Louisiana One of

1722-570: Is partly based on the Howe truss . The first Allan truss was completed on 13 August 1894 over Glennies Creek at Camberwell, New South Wales and the last Allan truss bridge was built over Mill Creek near Wisemans Ferry in 1929. Completed in March 1895, the Tharwa Bridge located at Tharwa, Australian Capital Territory , was the second Allan truss bridge to be built, the oldest surviving bridge in

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1804-695: Is practical for use with spans up to 250 feet (76 m) and was a common configuration for railroad bridges as truss bridges moved from wood to metal. They are statically determinate bridges, which lend themselves well to long spans. They were common in the United States between 1844 and the early 20th century. Examples of Pratt truss bridges are the Governor's Bridge in Maryland ; the Hayden RR Bridge in Springfield, Oregon , built in 1882;

1886-567: Is still in operation in the UK is the Stourbridge Town Branch Line from Stourbridge Junction going to Stourbridge Town . Operating on a single track, the journey is 0.8 miles (1.3 kilometres) long and the train takes around two and a half minutes to complete its journey. In North America, little-used branch lines are often sold by large railroads to become new common carrier short-line railroads of their own. Throughout

1968-427: Is sufficiently stiff then this vertical element may be eliminated. If the lower chord (a horizontal member of a truss) is sufficiently resistant to bending and shear, the outer vertical elements may be eliminated, but with additional strength added to other members in compensation. The ability to distribute the forces in various ways has led to a large variety of truss bridge types. Some types may be more advantageous when

2050-407: Is supported only at the ends and is fully independent of any adjacent spans. Each span must fully support the weight of any vehicles traveling over it (the live load ). In contrast, a continuous truss functions as a single rigid structure over multiple supports. This means that the live load on one span is partially supported by the other spans, and consequently it is possible to use less material in

2132-525: Is the Victoria Bridge on Prince Street, Picton, New South Wales . Also constructed of ironbark, the bridge is still in use today for pedestrian and light traffic. The Bailey truss was designed by the British in 1940–1941 for military uses during World War II. A short selection of prefabricated modular components could be easily and speedily combined on land in various configurations to adapt to

2214-770: The Australian Capital Territory and the oldest, longest continuously used Allan truss bridge. Completed in November 1895, the Hampden Bridge in Wagga Wagga, New South Wales , Australia, the first of the Allan truss bridges with overhead bracing, was originally designed as a steel bridge but was constructed with timber to reduce cost. In his design, Allan used Australian ironbark for its strength. A similar bridge also designed by Percy Allen

2296-532: The Bay of Plenty Region , lines were built inland to provide rail access to large logging operations. Today, many of the branch lines have been closed, including almost all of the general-purpose country lines. Those that remain serve ports or industries far from main lines such as coal mines, logging operations, large dairying factories, and steelworks . In Auckland and Wellington , two branch lines in each city exist solely for commuter passenger trains. For more, see

2378-621: The Dearborn River High Bridge near Augusta, Montana, built in 1897; and the Fair Oaks Bridge in Fair Oaks, California , built 1907–09. The Scenic Bridge near Tarkio, Montana , is an example of a Pratt deck truss bridge, where the roadway is on top of the truss. The queenpost truss , sometimes called "queen post" or queenspost, is similar to a king post truss in that the outer supports are angled towards

2460-1316: The Fort Wayne Street Bridge in Goshen, Indiana , the Schell Bridge in Northfield, Massachusetts , the Inclined Plane Bridge in Johnstown, Pennsylvania , the Easton–Phillipsburg Toll Bridge in Easton, Pennsylvania , the Connecticut River Bridge in Brattleboro, Vermont , the Metropolis Bridge in Metropolis, Illinois , and the Healdsburg Memorial Bridge in Healdsburg, California . A Post truss

2542-753: The Gladstone Branch in New Jersey; as well as the New Canaan Branch , Danbury Branch , and Waterbury Branch in Connecticut . The Long Island Rail Road also refers to its services as "branches". In Chile, there are a lot of branch lines on its main line, of only a few remain operational. Most only operating in turistic services (like the Antilhue-Valdivia branch line), others have been taken over by other railways (like

Tuatapere Branch - Misplaced Pages Continue

2624-1048: The Grand Trunk , Canadian National , or Canadian Pacific ) which would acquire formerly independent short line railways for use as branch lines, with the short line often continuing to exist as a subsidiary. For example, when the Canadian Pacific acquired the Algoma Eastern Railway (a short line) in 1930, it soon after abandoned much of the Algoma Eastern mainline, but retained sections close to Algoma Eastern–Canadian Pacific junctions as short branch lines or spurs. The National Transportation Act of 1967 provided government subsidies for branch lines. Western railway development in Canada worked in concert with land settlement and cultivation, as pioneers were settled near railway lines, often on land

2706-445: The Howe truss . The interior diagonals are under tension under balanced loading and vertical elements under compression. If pure tension elements (such as eyebars ) are used in the diagonals, then crossing elements may be needed near the center to accept concentrated live loads as they traverse the span. It can be subdivided, creating Y- and K-shaped patterns. The Pratt truss was invented in 1844 by Thomas and Caleb Pratt. This truss

2788-740: The New Zealand Railways Department (NZR) and officially opened on 20 October 1925. The line was run as two separate branches from Tuatapere: the Tuatapere Branch from Invercargill, and the Orawia Branch. During the days of steam motive power, most services on the branches were operated from a depot at Tuatapere. Trains were typically mixed, carrying both passengers and freight. One such train daily operated from Tuatapere to Invercargill and return, while another ran Invercargill to Tuatapere and return. Orawia

2870-788: The North South Line between Jurong East and Choa Chu Kang stations was operated as a separate line, known as the Branch line . It was merged into the North–South Line with the opening of the Woodlands Extension in 1996. The future Jurong Region Line and Cross Island Line will also have branch lines. New Zealand once had a very extensive network of branch lines, especially in the South Island regions of Canterbury , Otago , and Southland . Many were built in

2952-481: The River Tamar between Devon and Cornwall uses a single tubular upper chord. As the horizontal tension and compression forces are balanced these horizontal forces are not transferred to the supporting pylons (as is the case with most arch types). This in turn enables the truss to be fabricated on the ground and then to be raised by jacking as supporting masonry pylons are constructed. This truss has been used in

3034-704: The South Tseung Kwan O Spur Line to LOHAS Park station , opened in 2009. Earlier, a spur line was built in 1985 on the East Rail line to serve Racecourse station , bypassing Fo Tan station . Also, the Tsim Sha Tsui Extension  [ yue ] was built in 2004 on the East Rail line to serve East Tsim Sha Tsui station . However, after the Kowloon Southern Link was completed in 2009, this spur line turns into

3116-499: The United States , because wood was in abundance, early truss bridges would typically use carefully fitted timbers for members taking compression and iron rods for tension members , usually constructed as a covered bridge to protect the structure. In 1820, a simple form of truss, Town's lattice truss , was patented, and had the advantage of requiring neither high labor skills nor much metal. Few iron truss bridges were built in

3198-412: The list of New Zealand railway lines . Truss bridge The nature of a truss allows the analysis of its structure using a few assumptions and the application of Newton's laws of motion according to the branch of physics known as statics . For purposes of analysis, trusses are assumed to be pin jointed where the straight components meet, meaning that taken alone, every joint on the structure

3280-528: The Orawia Branch's existence. Traffic declined during the 1960s, and when steam motive power was replaced by D class diesel-electrics in June 1968, Tuatapere locomotive depot closed and services changed to operate out of Invercargill thrice weekly, on Monday, Wednesday and Friday. In May 1968 the cement works in Orawia closed, and deprived of its main source of traffic, the Orawia Branch closed on 1 October 1970. By

3362-685: The Pennsylvania truss adds to this design half-length struts or ties in the top, bottom, or both parts of the panels. It is named after the Pennsylvania Railroad , which pioneered this design. It was once used for hundreds of bridges in the United States, but fell out of favor in the 1930s and very few examples of this design remain. Examples of this truss type include the Lower Trenton Bridge in Trenton, New Jersey ,

Tuatapere Branch - Misplaced Pages Continue

3444-435: The San Rosendo-Talcahuano branch line, which has been taken over by Biotrén and the Laja-Talcahuano train service) however, there is one branch line that still remains as fully operative. The Talca-Constitución branch line, which uses trains with bus motors. Two extensions to the MTR rapid transit network were built as branches of existing lines: the Lok Ma Chau Spur Line to Lok Ma Chau station , which opened in 2007; and

3526-418: The Tuatapere Branch is also pretty clear in most places, and in Wakatapu some discarded rails and sleepers are at the old yard site, while a loading bank is at Ruahine and relocated station buildings still stand at Longwood and Orepuki. Branch line A branch line is a secondary railway line which branches off a more important through route, usually a main line . A very short branch line may be called

3608-407: The Tuatapere Branch was truncated to Riverton, and was known as the Riverton Branch until 1978, when it closed beyond Thornbury. The remaining portion of the line is now part of the Wairio Branch . The desire to open up regions west of Invercargill prompted construction of this line, with developers hoping to discover plentiful minerals and resources, and encourage more substantial settlement in

3690-421: The U.S. state of New Jersey . The line is a short branch of the Northeast Corridor Line , running from Princeton Junction northwest to Princeton with no intermediate stops. Also known as the "Dinky Line", at 2.9 mi (4.7 km) it is the shortest scheduled commuter rail line in the United States. The run takes 4 minutes, 47 seconds. Other than the Princeton Line, other surviving branch lines include

3772-469: The United States and Canada, branch lines link smaller towns too distant from the main line to be served efficiently, or to serve a certain industrial site such as a power station either because of a location away from the main line or to reduce congestion. They were typically built to lower standards, using lighter rail and shallow roadbeds when compared to main lines. Much of Canada's branch line history relates to large rail transport conglomerates (such as

3854-423: The United States before 1850. Truss bridges became a common type of bridge built from the 1870s through the 1930s. Examples of these bridges still remain across the US, but their numbers are dropping rapidly as they are demolished and replaced with new structures. As metal slowly started to replace timber, wrought iron bridges in the US started being built on a large scale in the 1870s. Bowstring truss bridges were

3936-406: The area. The first section of the line was built from Makarewa on the Kingston Branch to Riverton via Thornbury, the Wairio Branch junction, and opened on 9 June 1879. The line was opened in stages: Colac on 25 July 1881, Roundhill on 24 September 1883, Orepuki on 5 May 1885, Waihoaka on 1 October 1903 and Tuatapere on 1 October 1909. There was some dispute over where to commence a railway to

4018-461: The availability of machinery, and the cost of labor. In other cases, the appearance of the structure may take on greater importance and so influence the design decisions beyond mere matters of economics. Modern materials such as prestressed concrete and fabrication methods, such as automated welding , and the changing price of steel relative to that of labor have significantly influenced the design of modern bridges. A pure truss can be represented as

4100-632: The bridge companies marketed their designs, with the Wrought Iron Bridge Company in the lead. As the 1880s and 1890s progressed, steel began to replace wrought iron as the preferred material. Other truss designs were used during this time, including the camel-back. By the 1910s, many states developed standard plan truss bridges, including steel Warren pony truss bridges. In the 1920s and 1930s, Pennsylvania and several states continued to build steel truss bridges, using massive steel through-truss bridges for long spans. Other states, such as Michigan , used standard plan concrete girder and beam bridges, and only

4182-406: The bridge deck, they are susceptible to being hit by overheight loads when used on highways. The I-5 Skagit River bridge collapsed after such a strike; before the collapse, similar incidents had been common and had necessitated frequent repairs. Truss bridges consisting of more than one span may be either a continuous truss or a series of simple trusses. In the simple truss design, each span

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4264-493: The center, the opposite of the Pratt truss . In contrast to the Pratt truss, the diagonal web members are in compression and the vertical web members are in tension. Few of these bridges remain standing. Examples include Jay Bridge in Jay, New York ; McConnell's Mill Covered Bridge in Slippery Rock Township, Lawrence County, Pennsylvania ; Sandy Creek Covered Bridge in Jefferson County, Missouri ; and Westham Island Bridge in Delta, British Columbia , Canada. The K-truss

4346-435: The center. Many cantilever bridges, like the Quebec Bridge shown below, have two cantilever spans supporting a simple truss in the center. The bridge would remain standing if the simple truss section were removed. Bridges are the most widely known examples of truss use. There are many types, some of them dating back hundreds of years. Below are some of the more common designs. The Allan truss , designed by Percy Allan ,

4428-414: The compression members and to control deflection. It is mainly used for rail bridges, showing off a simple and very strong design. In the Pratt truss the intersection of the verticals and the lower horizontal tension members are used to anchor the supports for the short-span girders under the tracks (among other things). With the Baltimore truss, there are almost twice as many points for this to happen because

4510-399: The construction of a stadium, with the upper chords of parallel trusses supporting a roof that may be rolled back. The Smithfield Street Bridge in Pittsburgh, Pennsylvania , is another example of this type. An example of a lenticular pony truss bridge that uses regular spans of iron is the Turn-of-River Bridge designed and manufactured by the Berlin Iron Bridge Co. The Pauli truss is

4592-414: The earliest examples is the Old Blenheim Bridge , which with a span of 210 feet (64 m) and a total length of 232 feet (71 m) long was the second-longest covered bridge in the United States, until its destruction from flooding in 2011. The Busching bridge, often erroneously used as an example of a Long truss, is an example of a Howe truss, as the verticals are metal rods. A Parker truss bridge

4674-401: The elements, as in a Vierendeel truss . In the bridge illustrated in the infobox at the top, vertical members are in tension, lower horizontal members in tension, shear , and bending, outer diagonal and top members are in compression, while the inner diagonals are in tension. The central vertical member stabilizes the upper compression member, preventing it from buckling . If the top member

4756-432: The first president of the Canadian National Railway , said that although most branch lines cannot pay for themselves, they are even essential to make main lines pay. In the United States, abandonment of unproductive branch lines was a byproduct of deregulation of the rail industry through the Staggers Act . The Princeton Branch is a commuter rail line and service owned and operated by New Jersey Transit (NJT) in

4838-427: The late 19th century to open up inland regions for farming and other economic activities. The branches in the South Island regions were often general-purpose lines that carried predominantly agricultural traffic, but lines elsewhere were often built to serve a specific resource: on the West Coast , an extensive network of branch lines was built in rugged terrain to serve coal mines, while in the central North Island and

4920-437: The local Jewish community, with the goods shed , station building, and water tank all standing in relatively good condition, though the station building's exterior requires repairs and there are proposals to relocate it to a site on the Otago Central Rail Trail . The Orawia Branch's formation is distinct for much of its length, and at the terminus is the goods shed, with the ruins of the old cement works nearby. The formation of

5002-438: The mid-1970s, only 4,500 tonnes of traffic yearly were railed west of Riverton and the line was cut back to Riverton on 30 July 1976. There were expectations that forestry developments would create sufficient traffic from Riverton, but these failed to eventuate and the line from Thornbury was closed on 15 January 1978. A minor protest to keep the Thornbury to Riverton section open for tourism and potential private railway operations,

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5084-412: The needs at the site and allow rapid deployment of completed trusses. In the image, note the use of pairs of doubled trusses to adapt to the span and load requirements. In other applications the trusses may be stacked vertically, and doubled as necessary. The Baltimore truss is a subclass of the Pratt truss. A Baltimore truss has additional bracing in the lower section of the truss to prevent buckling in

5166-436: The railways had owned. However, by the mid-20th century, railways began neglecting lines in western agricultural regions. This was historically driven by factors such as the Crow Rate , which regulated the price railways could charge for shipping grain. Railways had little incentive to invest in rural Prairie branch lines, but were legally unable to abandon them under the National Transportation Act , which also did not provide

5248-507: The requirements of the customer the spur is serving. In heavily industrialized areas, it is not uncommon for one industrial spur to have multiple sidings to several different customers. Typically, spurs are serviced by local trains responsible for collecting small numbers of railcars and delivering them to a larger yard, where these railcars are sorted and dispatched in larger trains with other cars destined to similar locations. Because industrial spurs generally have less capacity and traffic than

5330-420: The rest of the line until the early 1950s, and around this time the daily Invercargill to Tuatapere and return goods train was withdrawn. This was partially offset by a Monday to Friday goods train from the Wairio Branch junction at Thornbury to Tuatapere. The Orawia Branch looked as if it could be closed at any time until a cement works was constructed in the town in 1956. It provided sufficient traffic to justify

5412-417: The settlement of Orawia. One of the two main proposals was to extend the Tuatapere line, and the other was to build a branch from Waikouro on the Wairio Branch. Ultimately, the Tuatapere proposal was accepted, and although construction was postponed due to World War I , work had recommenced by October 1919 and the Public Works Department was operating trains by mid-September 1924. The line was handed over to

5494-445: The short verticals will also be used to anchor the supports. Thus the short-span girders can be made lighter because their span is shorter. A good example of the Baltimore truss is the Amtrak Old Saybrook – Old Lyme Bridge in Connecticut , United States. The Bollman Truss Railroad Bridge at Savage, Maryland , United States is the only surviving example of a revolutionary design in the history of American bridge engineering. The type

5576-451: The simplest truss styles to implement, the king post consists of two angled supports leaning into a common vertical support. This type of bridge uses a substantial number of lightweight elements, easing the task of construction. Truss elements are usually of wood, iron, or steel. A lenticular truss bridge includes a lens-shape truss, with trusses between an upper chord functioning as an arch that curves up and then down to end points, and

5658-401: The standard for covered bridges built in central Ohio in the late 1800s and early 1900s. The Pegram truss is a hybrid between the Warren and Parker trusses where the upper chords are all of equal length and the lower chords are longer than the corresponding upper chord. Because of the difference in upper and lower chord length, each panel is not square. The members which would be vertical in

5740-409: The term lenticular truss and, according to Thomas Boothby, the casual use of the term has clouded the literature. The Long truss was designed by Stephen H. Long in 1830. The design resembles a Howe truss , but is entirely made of wood instead of a combination of wood and metal. The longest surviving example is the Eldean Covered Bridge north of Troy, Ohio , spanning 224 feet (68 m). One of

5822-489: The truss members are both above and below the roadbed it is called a through truss; an example of this is the Pulaski Skyway , and where the sides extend above the roadbed but are not connected, a pony truss or half-through truss. Sometimes both the upper and lower chords support roadbeds, forming a double-decked truss . This can be used to separate rail from road traffic or to separate the two directions of road traffic. Since through truss bridges have supports located over

5904-471: The truss. Continuous truss bridges were not very common before the mid-20th century because they are statically indeterminate , which makes them difficult to design without the use of computers . A multi-span truss bridge may also be constructed using cantilever spans, which are supported at only one end rather than both ends like other types of trusses. Unlike a continuous truss, a cantilever truss does not need to be connected rigidly, or indeed at all, at

5986-428: The upper chord under compression. In a cantilever truss the situation is reversed, at least over a portion of the span. The typical cantilever truss bridge is a "balanced cantilever", which enables the construction to proceed outward from a central vertical spar in each direction. Usually these are built in pairs until the outer sections may be anchored to footings. A central gap, if present, can then be filled by lifting

6068-430: The wood is employed for compression elements while other types may be easier to erect in particular site conditions, or when the balance between labor, machinery, and material costs has certain favorable proportions. The inclusion of the elements shown is largely an engineering decision based upon economics, being a balance between the costs of raw materials, off-site fabrication, component transportation, on-site erection,

6150-414: Was also easy to assemble. Wells Creek Bollman Bridge is the only other bridge designed by Wendel Bollman still in existence, but it is a Warren truss configuration. The bowstring truss bridge was patented in 1841 by Squire Whipple . While similar in appearance to a tied-arch bridge , a bowstring truss has diagonal load-bearing members: these diagonals result in a structure that more closely matches

6232-569: Was also indispensable in helping to develop the Waiau River valley and its settlements. A locomotive from the More & Sons sawmill tramway, which ran about 12 miles (19 km) from Longwood, is on display beside Riverton museum. The tramway was open from 1902 to 1960. Passenger services on the Orawia Branch did not last even a decade. By 1932, passengers were no longer carried and goods trains ran only twice weekly. Passengers could travel on

6314-504: Was further extended to Vaishali in 2011. The line is planned to be extended from Vaishali to Mohan Nagar via Sahibabad Station to link with the main line. The East West Line of the MRT system in Singapore has a two-station branch to Changi Airport . The first station, Expo , opened in 2001. It was extended to Changi Airport station the next year. From 1990 to 1996, the section of

6396-405: Was named after its inventor, Wendel Bollman , a self-educated Baltimore engineer. It was the first successful all-metal bridge design (patented in 1852) to be adopted and consistently used on a railroad. The design employs wrought iron tension members and cast iron compression members. The use of multiple independent tension elements reduces the likelihood of catastrophic failure. The structure

6478-683: Was popular with the Baltimore and Ohio Railroad . The Appomattox High Bridge on the Norfolk and Western Railway included 21 Fink deck truss spans from 1869 until their replacement in 1886. There are also inverted Fink truss bridges such as the Moody Pedestrian Bridge in Austin, Texas. The Howe truss , patented in 1840 by Massachusetts millwright William Howe , includes vertical members and diagonals that slope up towards

6560-502: Was repealed in 1994 in the wake of the North American Free Trade Agreement and budget-balancing initiatives in favour of a one-time payout by the federal government directly to farmers, to arrange transport of grain themselves. From the mid-1970s to the late 2010s, more than 9,300 kilometres (5,800 mi) of Prairie branch lines were abandoned or had a discontinuance of service. David Blyth Hanna ,

6642-439: Was served by a service from Tuatapere on Mondays, Wednesdays and Fridays. Along the line, a lucrative logging industry was established and many bush tramways were built to provide easy cartage of logs to the railway line. A timber mill was established in Tuatapere to process the logs and it provided much traffic for the railway. In the early days of the line, oil shale was a prominent source of freight from Orepuki. The railway

6724-628: Was to no avail. The section from Makarewa and Thornbury became part of the Wairio Branch. Some notable relics remained after closure. The most significant of these was the causeway and truss bridge that crossed the mouth of the Jacob River estuary in Riverton. The bridge and formation was removed in 2003, with one truss preserved by a local museum. The wooden viaduct near Tuatapere still exists. Tuatapere station and yard area are used by

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