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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.
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 momentarily unsupported and unguided and can slip through the gaps in the rails, and the latter because the assembly contains elements that can break or vibrate loose.
Level junctions are considered a maintenance issue by railroad companies as the inherent gaps tend to be hard on locomotive and rolling stock wheelsets. Switched diamonds partially solve these problems, but introduce new ones.
Flat crossings are particularly common in the United States where the lines of one company cross the lines of another company, and there is no particular need for the lines to be connected for through traffic.
Three examples of two tracks crossing another two tracks:
Flat crossings appear in some urban passenger rail systems, which can cause delays at peak hours as a train heading in one direction may have to wait for trains heading in another direction to clear the junction before it can cross. The junctions leading onto and off from the Loop of the Chicago 'L' are examples of this problem. The New York City Subway system mostly uses flying junctions, but in a few older parts of the system, flat crossings can still cause delays. Examples include the 142nd Street Junction and the Myrtle Avenue junction.
Level junctions are often found on tram or streetcar networks where lines cross or split. The MBTA in Boston has two of these underground on the Green Line, one where the E Line departs the central subway just west of Copley Station, and another where the C Line and D Line split west of Kenmore Station. While the latter crossing rarely causes delays, the former is at an intersection of four lines and cars often have to wait for others to pass at peak hours. Earlier such splits in Boston (such as the disused crossing west of Boylston Station) were built as flying junctions, but the two level splits were built as level junctions mostly to save money.
A diamond crossing between 1,435 mm (4 ft 8 1⁄2 in) standard gauge and 1,600 mm (5 ft 3 in), broad gauge exists at Ararat in Victoria, Australia [ citation needed ].
At Porthmadog, in the United Kingdom, there is a flat-crossing between the single track standard gauge Cambrian Line and the narrow-gauge Welsh Highland Railway (1 ft 11 1⁄2 in or 597 mm, also single track).
In Darby, Pennsylvania, USA, the SEPTA Route 11 line, using Pennsylvania trolley gauge of 5 ft 2 1⁄2 in (1,588 mm), crosses CSX Transportation using standard gauge.
In South Bay, San Diego at the South Bay Salt Works, as of 2001, survives the only crossing of narrow gauge track with standard gauge track, formerly utilized by the San Diego and Arizona Eastern Railway, in the United States.
In Sofia, Bulgaria, there are two diamond crossings between tracks of the Sofia tramway and a standard gauge railway line that connects Zaharna fabrika station with Zemlyane thermal power plant. One crossing is at Aleksandar Stamboliyski boulevard where the railway line crosses narrow gauge tram routes 8 and 10. The other is at Vazkresenie boulevard where it crosses tram routes 11 and 22. This second crossing is rather unique, as the tram track there is dual gauge. Route 11 uses narrow gauge while route 22 uses standard gauge. The railway line is rarely used, however. Most recently it saw use during the 2009 Gas Crisis when Zemlyane TPP temporarily switched from burning natural gas to burning mazut, which was delivered to the power plant by train.
In Queensland, Australia, a number of flat crossings between narrow gauge (610 mm (2 ft)) cane tramways and main lines (1,067 mm (3 ft 6 in)) have been replaced by drawbridges so that the rails of the main line are completely unbroken by gaps or weak spots: this allows the main line speeds to be raised.
A narrow-gauge railway is a railway with a track gauge narrower than standard 1,435 mm. Most narrow-gauge railways are between 600 mm and 1,067 mm.
Transport in Spain is characterised by an extensive network of roads, railways, rapid transit, air routes, and ports. Its geographic location makes it an important link between Europe, Africa, and the Americas. Major forms of transit generally radiate from the capital, Madrid, located in the centre of the country, to link with the capitals of the autonomous communities.
A standard-gauge railway is a railway with a track gauge of 1,435 mm. The standard gauge is also called Stephenson gauge after George Stephenson, International gauge, UIC gauge, uniform gauge, normal gauge and European gauge in Europe. It is the most widely used railway track gauge across the world, with approximately 55% of the lines in the world using it. All high-speed rail lines use standard gauge except those in Russia, Finland, Portugal and Uzbekistan. The distance between the inside edges of the rails is defined to be 1435 mm except in the United States and on some heritage British lines, where it is still defined in U.S. customary units as exactly "four feet eight and one half inches".
A broad-gauge railway is a railway with a track gauge broader than the 1,435 mm standard-gauge railways.
A railroad switch (AE), turnout, or [set of] points (BE) is a mechanical installation enabling railway trains to be guided from one track to another, such as at a railway junction or where a spur or siding branches off.
In rail transport, track gauge or track gage is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails.
A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a mass transit or rapid transit system, which has alignments in its own corridors, fully or almost fully segregated from the outside environment. Third rail systems are always supplied from direct current electricity.
A dual gauge railway is a track that allows the passage of trains of two different track gauges. It is sometimes called a "mixed gauge" track. A dual gauge track consists of three rails. There will be two vital rails, one for each gauge close together and a third rail, a "common" rail further away. Sometimes, four rails are required using two outer and two inner rails to create the dual gauge. Dual gauge is not to be confused with a "third rail" or "check or guard rails".
The Cincinnati, Lebanon and Northern Railway (CL&N) was a local passenger and freight-carrying railroad in the southwestern part of the U.S. state of Ohio, connecting Cincinnati to Dayton via Lebanon. It was built in the late 19th century to give the town of Lebanon and Warren County better transportation facilities. The railroad was locally known as the "Highland Route", since it followed the ridge between the Little and Great Miami rivers, and was the only line not affected by floods such as the Great Dayton Flood of 1913.
With railways, a break of gauge occurs where a line of one gauge meets a line of a different gauge: specifically a different track gauge. Trains and rolling stock cannot run through without some form of conversion between gauges, and freight and passengers must otherwise be transshipped. A break of gauge adds delays, cost, and inconvenience.
Gauntlet track or interlaced track is an arrangement in which railway tracks run parallel on a single track bed and are interlaced such that only one pair of rails may be used at a time. Since this requires only slightly more width than a single track, all rails can be carried on the same crossties/sleepers. Trains run on the discrete pair of rails appropriate to their direction, track gauge or loading gauge.
A double-track railway usually involves running one track in each direction, compared to a single-track railway where trains in both directions share the same track.
Railways with a railway track gauge of 5 ft were first constructed in the United Kingdom and the United States. This gauge is also commonly called Russian gauge because this gauge was later chosen as the common track gauge for the Russian Empire and its neighbouring countries. The gauge was redefined by Soviet Railways to be 1,520 mm.
The South Pacific Coast Railroad (SPC) was a 3 ft narrow gauge steam railroad running between Santa Cruz, California and Alameda, with a ferry connection in Alameda to San Francisco. The railroad was created as the Santa Clara Valley Railroad, founded by local strawberry growers as a way to get their crops to market in San Francisco and provide an alternative to the Southern Pacific Railroad. In 1876, James Graham Fair, a Comstock Lode silver baron, bought the line and extended it into the Santa Cruz Mountains to capture the significant lumber traffic coming out of the redwood forests. The narrow-gauge line was originally laid with 52-pound-per-yard (26 kg/m) rail on 8-foot (2.44 m) redwood ties; and was later acquired by the Southern Pacific and converted to 4 ft 8 1⁄2 instandard gauge.
Rail transport in Australia involves a number of narrow-gauge railways. In some states they formed the core statewide network, but in the others they were either a few government branch lines, or privately owned and operated branch lines, often for mining, logging or industrial use.
Upsala-Lenna Järnväg (ULJ) is a narrow-gauge heritage railway in Uppsala County, Sweden. It is 33 km (21 mi) long and is a part of the once extensive Roslagen network. The gauge is the 891 mm, unique to Sweden. The railway is run by the SRJmf society.
5 ft 6 in / 1,676 mm, a broad gauge, is the track gauge used in India, Pakistan, western Bangladesh, Sri Lanka, Argentina, Chile, and on BART in the San Francisco Bay Area.
The vast majority of North American railroads are standard gauge. Exceptions include some streetcar, subway and rapid transit systems, mining and tunneling operations, and some narrow-gauge lines particularly in the west, e.g. the isolated White Pass and Yukon Route system, and the former Newfoundland Railway.
A railway or railroad is a track where the vehicle travels over two parallel steel bars, called rails. The rails support and guide the wheels of the vehicles, which are traditionally either trains or trams. Modern light rail is a relatively new innovation which combines aspects of those two modes of transport. However fundamental differences in the track and wheel design are important, especially where trams or light railways and trains have to share a section of track, as sometimes happens in congested areas.
The Southern California Railway Museum, formerly known as the Orange Empire Railway Museum, at 2201 South "A" Street in Perris, California, is a railroad museum founded in 1956 at the Pinacate Station as the "Orange Empire Trolley Museum." The museum also operates a heritage railroad on the museum grounds.