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Overpass
An overpass, called an overbridge or flyover (for a road only) in the United Kingdom and some other Commonwealth countries, is a bridge, road, railway or similar structure that is over another road or railway. An ''overpass'' and '' underpass'' together form a grade separation. Stack interchanges are made up of several overpasses. History The world's first railroad flyover was constructed in 1843 by the London and Croydon Railway at Norwood Junction railway station to carry its atmospheric railway vehicles over the Brighton Main Line. Highway and road In North American usage, a ''flyover'' is a high-level overpass, built above main overpass lanes, or a bridge built over what had been an at-grade intersection. Traffic engineers usually refer to the latter as a '' grade separation''. A flyover may also be an extra ramp added to an existing interchange, either replacing an existing cloverleaf loop (or being built in place of one) with a higher, faster ramp that eventua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloverleaf Interchange
A cloverleaf interchange is a two-level interchange (road), interchange in which all turns are handled by slip roads. To go left (in right-hand traffic; reverse directions in left-driving regions), vehicles first continue as one road passes over or under the other, then exit right onto a one-way three-quarter loop ramp (270°) and merge onto the intersecting road. The objective of a cloverleaf is to allow two highways to cross without the need for any traffic to be stopped by traffic lights. The limiting factor in the capacity of a cloverleaf interchange is traffic weaving. Overview Cloverleaf interchanges, viewed from overhead or on maps, resemble the leaf, leaves of a four-leaf clover or less often a 3-leaf clover. In the United States, cloverleaf interchanges existed long before the Interstate highway, Interstate system. They were originally created for busier interchanges that the original diamond interchange system could not handle. Their chief advantage was that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underpass
A subway, also known as an underpass, is a grade-separated pedestrian crossing running underneath a road or railway in order to entirely separate pedestrians and cyclists from motor or train traffic. Terminology In the United States, as used by the California Department of Transportation and in parts of Pennsylvania such as Harrisburg, Duncannon and Wyoming County, subway refers to a depressed road undercrossing. Where they are built elsewhere in the country, the term 'pedestrian underpass' is more likely to be used, because "subway" in North America refers to rapid transit systems such as the New York City Subway or the Toronto subway. This usage also occurs in Scotland, where the underground railway in Glasgow is referred to as the Glasgow Subway. Effects Pedestrian underpasses allow for the uninterrupted flow of both pedestrians and vehicle traffic. However, they are normally considered a last resort by modern urban planners as they can be expensive and cause graff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
At-grade Intersection
An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections are often delineated by gores and may be classified by road segments, traffic controls and lane design. This article primarily reflects practice in jurisdictions where vehicles are driven on the right. If not otherwise specified, "right" and "left" can be reversed to reflect jurisdictions where vehicles are driven on the left. Types Road segments One way to classify intersections is by the number of road segments (arms) that are involved. * A three-way intersection is a junction between three road segments (arms): a T junction when two arms form one road, or a Y junction, the latter also known as a fork if approached from the stem of the Y. * A four-way intersection, or crossroads, usually involves a crossing over of two streets or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Railway
An atmospheric railway uses differential air pressure to provide power for propulsion of a railway vehicle. A static power source can transmit motive power to the vehicle in this way, avoiding the necessity of carrying mobile power generating equipment. The air pressure, or partial vacuum (i.e., negative relative pressure) can be conveyed to the vehicle in a continuous pipe, where the vehicle carries a piston running in the tube. Some form of re-sealable slot is required to enable the piston to be attached to the vehicle. Alternatively the entire vehicle may act as the piston in a large tube or be coupled Magnetic coupling, electromagnetically to the piston. Several variants of the principle were proposed in the early 19th century, and a number of practical forms were implemented, but all were overcome by unforeseen disadvantages and discontinued within a few years. A modern proprietary system has been developed and is in use for short-distance applications. Porto Alegre Metro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Level Crossing
A level crossing is an intersection where a railway line crosses a road, Trail, path, or (in rare situations) airport runway, at the same level, as opposed to the railway line or the road etc. crossing over or under using an Overpass#Railway, overpass or tunnel. The term also applies when a light rail line with separate Right-of-way (railroad), right-of-way or reserved track crosses a road in the same fashion. Other names include railway level crossing, railway crossing (chiefly international), grade crossing or railroad crossing (chiefly American), road through railroad, criss-cross, train crossing, and RXR (abbreviated). There are more than 100,000 level crossings in Europe and more than 200,000 in North America. Road-grade crossings are considered incompatible with high-speed rail and are virtually non-existent in European high-speed train operations. File:The 5.20 for West Kirby leaving Hoylake - geograph.org.uk - 1503619.jpg, A level crossing at Hoylake, Merseyside, Engl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grade Separation
In civil engineering (more specifically highway engineering), grade separation is a method of aligning a junction of two or more surface transport axes at different heights ( grades) so that they will not disrupt the traffic flow on other transit routes when they cross each other. The composition of such transport axes does not have to be uniform; it can consist of a mixture of roads, footpaths, railways, canals, or airport runways. Bridges (or overpasses, also called flyovers), tunnels (or underpasses), or a combination of both can be built at a junction to achieve the needed grade separation. In North America, a grade-separated junction may be referred to as a ''grade separation'' or as an '' interchange'' – in contrast with an ''intersection'', '' at-grade'', a '' diamond crossing'' or a ''level crossing'', which are not grade-separated. Effects Advantages Roads with grade separation generally allow traffic to move freely, with fewer interruptions, and at higher overall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freeway Interchange
In the field of road transport, an interchange (American English) or a grade-separated junction (British English) is a road junction that uses grade separations to allow for the movement of traffic between two or more roadways or highways, using a system of interconnecting roadways to permit traffic on at least one of the routes to pass through the junction without interruption from crossing traffic streams. It differs from a standard intersection, where roads cross at grade. Interchanges are almost always used when at least one road is a controlled-access highway (freeway) or a limited-access highway (expressway), though they are sometimes used at junctions between surface streets. Terminology ''Note:'' The descriptions of interchanges apply to countries where vehicles drive on the right side of the road. For left-side driving, the layout of junctions is mirrored. Both North American (NA) and British (UK) terminology is included. ; Freeway junction, highway interchange ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge
A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it. The earliest bridges were likely made with fallen trees and stepping stones. The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge, dating from the 13th century BC, in the Peloponnese is one of the oldest arch bridges in existence and use. Etymology The ''Oxford English Dictionary'' traces the origin of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumberland Highway
Cumberland Highway is a long urban highway located in Sydney, New South Wales, Australia. The highway links Pacific Highway (Australia), Pacific Highway and Pacific Motorway (Sydney–Newcastle), Pacific Motorway (Highway 1 (New South Wales), M1) at Pearces Corner, Wahroonga, New South Wales, Wahroonga in the northeast with Hume Highway at Liverpool, New South Wales, Liverpool in the southwest. This name covers a few consecutive roads and is widely known to most drivers, but the entire allocation is also known – and signposted – by the names of its constituent parts: Pennant Hills Road, James Ruse Drive, Briens Road, Old Windsor Road, Hart Drive, Freame Street, Emert Street, Jersey Road, Betts Road, Warren Road, Smithfield Road, Palmerston Road, (New) Cambridge Street, Joseph Street and Orange Grove Road. The entire length of Cumberland Highway is designated part of Route number, route A28. The name of the highway is derived from the Cumberland Plain and Cumberland County ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sydney
Sydney is the capital city of the States and territories of Australia, state of New South Wales and the List of cities in Australia by population, most populous city in Australia. Located on Australia's east coast, the metropolis surrounds Sydney Harbour and extends about 80 km (50 mi) from the Pacific Ocean in the east to the Blue Mountains (New South Wales), Blue Mountains in the west, and about 80 km (50 mi) from Ku-ring-gai Chase National Park and the Hawkesbury River in the north and north-west, to the Royal National Park and Macarthur, New South Wales, Macarthur in the south and south-west. Greater Sydney consists of 658 suburbs, spread across 33 local government areas. Residents of the city are colloquially known as "Sydneysiders". The estimated population in June 2024 was 5,557,233, which is about 66% of the state's population. Estimated resident population, 30 June 2017. The city's nicknames include the Emerald City and the Harbour City. There is ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flat Junction
A level junction (or in the United Kingdom a flat crossing) is a railway junction that has a track configuration in which merging or crossing railroad lines provide track connections with each other that require trains to cross over in front of opposing traffic at grade (i.e. on the level). The cross-over structure is sometimes called a diamond junction or diamond crossing in reference to the diamond-shaped center. The two tracks need not necessarily be of the same gauge. A diamond crossing is also used as a component of a double junction, like the one illustrated on the right. The opposite of a level junction is a flying junction, where individual tracks rise or fall to pass over or under other tracks. Risks Conflicting routes must be controlled by interlocked signals to prevent collisions. Level junctions, particularly those of fine angles or near right angles, create derailment risks and impose speed restrictions. The former can occur as the flanges of the wheels are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flying Junction
A flying junction or flyover is a railway junction at which one or more diverging or converging tracks in a multiple-track route cross other tracks on the route by bridge to avoid conflict with other train movements. A more technical term is "grade separation, grade-separated junction". A burrowing junction or dive-under occurs where the diverging line passes below the main line. The alternative to grade separation is a level junction or flat junction, where tracks cross At-grade intersection, at grade, and conflicting routes must be protected by interlocked railway signal, signals. Complexity Simple flying junctions may have a single track pass over or under other tracks to avoid conflict; complex flying junctions may have elaborate infrastructure to allow multiple routings without trains coming into conflict, in the manner of a highway stack interchange. Flying junction without crossings Where two lines each of two tracks merge with a flying junction, they can become a Quadr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
