A flying junction or flyover is a

railway junction A junction, in the context of rail transport, is a place at which two or more rail routes converge or diverge. This implies a physical connection between the tracks of the two routes (assuming they are of the same gauge), provided by ''points'' ( ...

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-separated junction A grade-separated junction is a transport junction where at least one bridge or tunnel is used to separate traffic flows (known as grade separation). Relevant articles include: * Road interchanges Interchange may refer to: Transport * Interch ...

". 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 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 o ...

or flat junction, where tracks cross at grade, and conflicting routes must be protected by interlocked

signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...

Complexity

Simple flying junctions may have a single track pass over or under other tracks to avoid conflict, while complex flying junctions may have an 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 four-track railway together, the tracks paired by direction. This happens regularly in the Netherlands (see

Examples Example may refer to: * '' exempli gratia'' (e.g.), usually read out in English as "for example" * .example, reserved as a domain name that may not be installed as a top-level domain of the Internet ** example.com, example.net, example.org, e ...

below).

High-speed rail

Nearly all junctions with high-speed railways are grade-separated. On the French

Lignes à Grande Vitesse The first French high-speed rail line opened in 1981, between Paris's and Lyon's suburbs. The LGV Sud-Est was at that time the only high-speed rail line in Europe. As of June 2021, the French high-speed rail network comprises 2,800 km of '' ...

(

TGV The TGV (french: Train à Grande Vitesse, "high-speed train"; previously french: TurboTrain à Grande Vitesse, label=none) is France's intercity high-speed rail service, operated by SNCF. SNCF worked on a high-speed rail network from 1966 to 19 ...

) high-speed network, the principal junction on the

LGV Sud-Est The LGV Sud-Est (French: ''Ligne à Grande Vitesse Sud-Est''; English: ''South East high-speed line)'' is a French high-speed rail line which connects the Paris and Lyon areas. It was France's first high-speed rail line. The inauguration of th ...

, at Pasilly where the line to Dijon diverges, and on the

LGV Atlantique The LGV Atlantique (French: ''Ligne à Grande Vitesse''; English: Atlantic high-speed line) is a high-speed rail line running from Paris (Gare Montparnasse) to Western France. It opened in 1989–1990 and comprises two stations: Massy TGV statio ...

at Courtalain where the line to Le Mans diverges, are fully grade-separated with special high-speed switches (''points'' in British terminology) that permit the normal line speed of on the main line, and a diverging speed of .See "

Courtalain Courtalain () is a former commune in the Eure-et-Loir department in northern France. On 1 January 2017, it was merged into the new commune Commune nouvelle d'Arrou. The LGV network has four grade-separated high-speed triangles: Fretin (near Lille), Coubert (southeast Paris), Claye-Souilly (northeast Paris) and Angles (Avignon). A fifth, Vémars (northeast Paris), is grade-separated except for a single-track link on the least-used side, linking Paris Gare du Nord and Paris CDG airport.

Examples

;Australia *

Bowen Hills railway station Bowen Hills railway station is located on the North Coast line in Queensland, Australia. It serves the Brisbane suburb of Bowen Hills. North of the station, the Ferny Grove line branches off. The station is one of four inner city stations th ...

Brisbane Brisbane ( ) is the capital and most populous city of the Australian state of Queensland, and the third-most populous city in Australia and Oceania, with a population of approximately 2.6 million. Brisbane lies at the centre of the South ...

Burnley railway station Burnley railway station is the junction station for the Lilydale, Belgrave, Alamein and Glen Waverley lines in Victoria, Australia. It serves the inner eastern Melbourne suburb of Burnley, and it opened on 1 May 1880 as Burnley Street. It wa ...

Melbourne Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...

* Camberwell railway station in Melbourne * Sydney Central Station *

Glenfield railway station, Sydney Glenfield railway station is a junction station serving the Sydney suburb of Glenfield in Australia. It is served by Sydney Trains T8 Airport & South, T2 Inner West & Leppington and T5 Cumberland line services, and by limited NSW TrainLi ...

* Strathfield railway station *

Sandgate Flyover The Sandgate Flyover is a grade-separated railway flyover that carries the Main North line across the Kooragang Island line, located in Sandgate, in the City of Newcastle local government area of New South Wales, Australia. Description Si ...

Newcastle Newcastle usually refers to: *Newcastle upon Tyne, a city and metropolitan borough in Tyne and Wear, England *Newcastle-under-Lyme, a town in Staffordshire, England *Newcastle, New South Wales, a metropolitan area in Australia, named after Newcastle ...

– main line flies over coal branch line *

Goodwood railway station Goodwood railway station is the junction station for the Belair, Seaford and Flinders lines. The Belair line diverges south-east towards Millswood, while the Seaford and Flinders lines diverge south-west towards Clarence Park. The Glenelg ...

Adelaide Adelaide ( ) is the capital city of South Australia, the state's largest city and the fifth-most populous city in Australia. "Adelaide" may refer to either Greater Adelaide (including the Adelaide Hills) or the Adelaide city centre. The dem ...

;Canada

* Columbia station in New Westminster, BC – Expo Line branches for King George (top) and Production Way–University (bottom) * Bridgeport station in Richmond, BC –

Canada Line The Canada Line is a rapid transit line in Metro Vancouver, British Columbia, Canada, that is part of the SkyTrain system. The line is owned by TransLink and InTransitBC and is operated by ProTrans BC. Coloured turquoise on route maps, it op ...

branches for YVR–Airport and Richmond–Brighouse ;Denmark * Hvidovre, Copenhagen () * Junction of M1 and M2 lines on the

Copenhagen Metro The Copenhagen Metro ( da, Københavns Metro, ) is a 24/7 rapid transit system in Copenhagen, Denmark, serving the municipalities of Copenhagen, Frederiksberg, and Tårnby. The original system opened in October 2002, serving nine stations on t ...

* Lunderskov () * Roskilde, south of () * Sydhavnen, Copenhagen () * Vigerslev, Copenhagen () Finland * Railway junction of two main lines at Kytömaa, Kerava ;France (LGV Triangles) * Triangle de Fretin, Lille, connecting Paris, Brussels and London * Triangle de Coubert, Paris * Triangle des Angles, Avignon, with two parallel viaducts * Triangle de Claye-Souilly, Paris, partial four-way junction * Triangle de Vémars, Paris ;Germany * Bruchsal Rollenberg junction ;Hong Kong * Where

Airport Express The AirPort Express is a Wi-Fi base station product from Apple Inc., part of the AirPort product line. While more compact and in some ways simpler than another Apple Wi-Fi base station, the AirPort Extreme, the Express offers audio output cap ...

and

Tung Chung line The Tung Chung line is one of the ten lines of the MTR system in Hong Kong, linking the town of Tung Chung with central Hong Kong. A part of the Tung Chung line was built along with the Kap Shui Mun Bridge and the Tsing Ma Bridge. The line c ...

diverge from each other at

Tai Ho Wan Tai or TAI may refer to: Arts and entertainment *Tai (comics) a fictional Marvel Comics supervillain *Tai Fraiser, a fictional character in the 1995 film ''Clueless'' *Tai Kamiya, a fictional character in ''Digimon'' Businesses and organisations ...

Tseung Kwan O line The Tseung Kwan O line is one of the eleven lines of the MTR system in Hong Kong, indicated by the colour purple. It is currently long, taking 15 minutes to travel throughout the entire line. The line runs from North Point on the Hong Kong Is ...

to the east of

Tseung Kwan O station Tseung Kwan O (; : ) is a station on the MTR located at the town centre of the Tseung Kwan O New Town in the New Territories of Hong Kong. The previous station is and the line splits after this station to and . The entrances to the station ...

;Netherlands There are between 25 and about 40 flying junctions on Dutch railways, depending on how more complex examples are counted. * Near

Harmelen Harmelen is a town in the Dutch province of Utrecht. It is a part of the municipality of Woerden, and lies about 6 km east of Woerden. In 2001, the town of Harmelen had 6557 inhabitants. The built-up area of the town was 1.11 km², and c ...

. Before conversion to a flying junction, this was the site of the

Harmelen train disaster The Harmelen train disaster, on 8 January 1962, was the worst railway accident in the history of the Netherlands. Harmelen, in the central Netherlands, is the location of a railway junction where a branch to Amsterdam leaves the Rotterdam to Ut ...

. * At

Breukelen railway station Breukelen is a railway station located in Breukelen, Netherlands. The station was opened on 18 December 1843 and is on the Amsterdam–Arnhem railway The Amsterdam–Arnhem railway, also referred to as the Amsterdam–Elten railway or ''Rhijnspo ...

* At

Lage Zwaluwe railway station Lage Zwaluwe is a railway station near Lage Zwaluwe and Moerdijk, Netherlands. The station was opened in 1883 and is located on the Breda–Rotterdam railway between Breda and Dordrecht and the Antwerp–Lage Zwaluwe railway. The services are o ...

Flying junctions where the merged lines become a four track railway: * Near

Den Haag Laan van NOI railway station Den Haag Laan van NOI railway station is a railway station in the Netherlands, on the border between The Hague and the town of Voorburg. It is served by the Nederlandse Spoorwegen (Dutch railway) and by the RandstadRail light-rail network. The sta ...

* North of

Leiden Leiden (; in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden has a population of 119,713, but the city forms one densely connected agglomeration wi ...

where lines from Haarlem and

Schiphol Amsterdam Airport Schiphol , known informally as Schiphol Airport ( nl, Luchthaven Schiphol, ), is the main international airport of the Netherlands. It is located southwest of Amsterdam, in the municipality of Haarlemmermeer in the province ...

merge * At

Boxtel railway station Boxtel railway station is located in Boxtel, Netherlands. The station was opened on 1 May 1865 and is located on the Breda–Eindhoven railway (between Tilburg and Eindhoven) and the Utrecht–Boxtel railway. The station is currently operated by ...

where lines from

's-Hertogenbosch s-Hertogenbosch (), colloquially known as Den Bosch (), is a city and municipality in the Netherlands with a population of 157,486. It is the capital of the province of North Brabant and its fourth largest by population. The city is south of th ...

and

Tilburg Tilburg () is a city and municipality in the Netherlands, in the southern province of North Brabant. With a population of 222,601 (1 July 2021), it is the second-largest city or municipality in North Brabant after Eindhoven and the seventh-larg ...

merge * West of Gouda where lines from

Rotterdam Rotterdam ( , , , lit. ''The Dam on the River Rotte'') is the second largest city and municipality in the Netherlands. It is in the province of South Holland, part of the North Sea mouth of the Rhine–Meuse–Scheldt delta, via the ''"Ne ...

and

The Hague The Hague ( ; nl, Den Haag or ) is a city and municipality of the Netherlands, situated on the west coast facing the North Sea. The Hague is the country's administrative centre and its seat of government, and while the official capital o ...

merge More complex flying junctions, with tracks from four directions joining: * Around

Amsterdam Sloterdijk railway station Amsterdam Sloterdijk is a major railway junction to the west of Amsterdam Centraal station. It is at a rail-rail crossing, with an additional chord (Hemboog). It is on the railway line from Amsterdam Centraal to Haarlem and the last station before ...

* Around

Duivendrecht railway station Duivendrecht station ( Dvd) is a combined rail and metro station in Duivendrecht, Netherlands. The station opened on 23 May 1993 as part of the extension of the Zuidtak of the Amsterdam Ringspoorbaan, between Amsterdam RAI and Weesp. This station ...

* Northwest exit of

Utrecht Centraal railway station Utrecht Centraal, officially Station Utrecht Centraal (), is the transit hub that integrates three bicycle parkings, two bus stations, two tram stops and the central railway station for the city of Utrecht in the province of Utrecht, Netherlan ...

* West and northwest exit of

Rotterdam Centraal railway station Rotterdam Centraal railway station () is the main railway station of the city Rotterdam in South Holland, Netherlands. The station received an average of 112,000 passengers daily in 2019. The current station building, located at Station Square, ...

* At both sides of

Weesp railway station Weesp is a railway station in Weesp, Netherlands. The station has two island platforms and it has a total of six tracks, from which two tracks are for passing trains. The first station in Weesp opened on June 10, 1874, when the Gooilijn from Ams ...

(see diagram at right) ;Norway * Lillestrøm () * Lysaker () * Sandvika, east of and west of () () ;Sweden * Flemingsberg () * Järna, north of () * Järna, south of () * Lund () * Hyllie () * Myrbacken () * Lernacken () * Södertälje hamn () * Södertälje syd () * Tomteboda () ;Taiwan * Start of Shalun line, south of Zhongzhou railway station ;United Kingdom * Pelaw Junction where both the

Tyne and Wear Metro The Tyne and Wear Metro is an overground and underground light rail rapid transit system serving Newcastle upon Tyne, Gateshead, North Tyneside, South Tyneside, and the City of Sunderland (together forming Tyne and Wear). The network opened in ...

green line to South Hylton joins the

Durham Coast Line The Durham Coast Line is an approximately railway line running between Newcastle and in North East England. Heavy rail passenger services, predominantly operated Northern Trains, and some freight services operate over the whole length of the li ...

and yellow line continues to South Shields – both diverging on the bridge itself * Springhead Junction on the

North Kent Line The North Kent Line is a railway line which branches off the South East Main Line at St Johns junction west of Lewisham station in Greater London and runs to Rochester Bridge Junction near Strood, Medway where it links to the Chatham Main Li ...

* Southfleet Junction on the

HS1 High Speed 1 (HS1), legally the Channel Tunnel Rail Link (CTRL), is a high-speed railway linking London with the Channel Tunnel. It is part of a line carrying international passenger traffic between the United Kingdom and mainland Europe; ...

* Norton Bridge Junction near Stone, Staffordshire * Hamilton Square underground station,

Birkenhead Birkenhead (; cy, Penbedw) is a town in the Metropolitan Borough of Wirral, Merseyside, England; historically, it was part of Cheshire until 1974. The town is on the Wirral Peninsula, along the south bank of the River Mersey, opposite Liver ...

, on

Merseyrail Merseyrail is a Urban rail in the United Kingdom, commuter rail network serving the Liverpool City Region and adjacent areas of Cheshire and Lancashire. Merseyrail operates 66 railway stations across two lines – the Northern Line (Merseyrail ...

Aynho Junction Aynho (, formerly spelt ''Aynhoe'') is a village and civil parish in West Northamptonshire, England, on the edge of the Cherwell valley south-east of the north Oxfordshire town of Banbury and southwest of Brackley. Along with its neighbour ...

in Aynho,

Northamptonshire Northamptonshire (; abbreviated Northants.) is a county in the East Midlands of England. In 2015, it had a population of 723,000. The county is administered by two unitary authorities: North Northamptonshire and West Northamptonshire. It is ...

Worting Junction The West of England line (also known as the West of England Main Line) is a British railway line from , Hampshire, to in Devon, England. Passenger services run between London Waterloo station and Exeter; the line intersects with the Wessex Ma ...

near Basingstoke,

Hampshire Hampshire (, ; abbreviated to Hants) is a ceremonial and non-metropolitan county in western South East England on the coast of the English Channel. Home to two major English cities on its south coast, Southampton and Portsmouth, Hampshire ...

(the flyover is called Battledown Flyover) *

Cogload Junction Cogload Junction is a railway junction in Durston, Somerset, England. It is where the 1906-opened London to Penzance Line via Castle Cary joins the original line that runs via Bristol Temple Meads. A flyover was constructed in 1931 convert ...

near

Taunton Taunton () is the county town of Somerset, England, with a 2011 population of 69,570. Its thousand-year history includes a 10th-century monastic foundation, Taunton Castle, which later became a priory. The Normans built a castle owned by the ...

Weaver Junction Weaver Junction is a railway junction connecting the West Coast Main Line (WCML) with the Weaver Junction–Liverpool line, opening on 1 April 1869. Trains bound for Liverpool from London diverge from the WCML at this junction. Weaver Junction i ...

near

Dutton, Cheshire Dutton is a civil parish and village within the unitary authority of Cheshire West and Chester, in the ceremonial county of Cheshire, England, about east of Runcorn. Dutton is on the River Weaver and was home to Dutton Hall, built in 1513 and mo ...

* Shortlands Junction in south London * Northwest of Harrow-on-the-Hill, in the north London suburbs * Hitchin flyover, Hertfordshire. * Werrington Junction dive-under, under construction north of

Peterborough Peterborough () is a cathedral city in Cambridgeshire, east of England. It is the largest part of the City of Peterborough unitary authority district (which covers a larger area than Peterborough itself). It was part of Northamptonshire until ...

(north of Hitchin) *

Reading Reading is the process of taking in the sense or meaning of letters, symbols, etc., especially by sight or touch. For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spelling ...

West Junction * Bleach Green Viaducts & Junction,

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Northern Ireland Northern Ireland ( ga, Tuaisceart Éireann ; sco, label= Ulster-Scots, Norlin Airlann) is a part of the United Kingdom, situated in the north-east of the island of Ireland, that is variously described as a country, province or region. Nort ...

;United States * Northeast U.S. (

Amtrak The National Railroad Passenger Corporation, doing business as Amtrak () , is the national passenger railroad company of the United States. It operates inter-city rail service in 46 of the 48 contiguous U.S. States and nine cities in Canada ...

) ** Along the New York–

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

section of the Northeast Corridor, and on the Philadelphia–

Harrisburg Harrisburg is the capital city of the Commonwealth of Pennsylvania, United States, and the county seat of Dauphin County. With a population of 50,135 as of the 2021 census, Harrisburg is the 9th largest city and 15th largest municipality in Pe ...

section of the

Keystone Corridor The Keystone Corridor is a 349-mile (562 km) railroad corridor between Philadelphia and Pittsburgh, Pennsylvania, that consists of two rail lines: Amtrak and SEPTA's Philadelphia-to-Harrisburg main line, which hosts SEPTA's Paoli/Thorndale ...

. Both converge at

Zoo Junction Zoo Junction is a junction on Amtrak's Northeast Corridor in Philadelphia, Pennsylvania where the Northeast Corridor meets the Keystone Corridor (ex- Pennsylvania Railroad main line). History Zoo Junction is a flying junction, where mul ...

near

30th Street Station 3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious or cultural significance in many societie ...

in Philadelphia. All were built by the former Pennsylvania Railroad and are now maintained by Amtrak. *

Boston Boston (), officially the City of Boston, is the state capital and most populous city of the Commonwealth of Massachusetts, as well as the cultural and financial center of the New England region of the United States. It is the 24th- mo ...

, Massachusetts area ** An abandoned underground junction on the

Tremont Street subway The Tremont Street subway in Boston's MBTA subway system is the oldest subway tunnel in North America and the third oldest still in use worldwide to exclusively use electric traction (after the City and South London Railway in 1890, and the Bud ...

approaching the

Pleasant Street incline The Pleasant Street incline or Pleasant Street portal was the southern access point for the Tremont Street subway in Boston, Massachusetts, which became part of the Green Line after the incline was closed. The portal and the section of tunnel co ...

** The B branch splits off from the C and D branches of the MBTA Green Line via an underground flying junction just west of

Kenmore station Kenmore station is a light rail station on the MBTA Green Line, located under Kenmore Square in the Fenway/Kenmore neighborhood of Boston, Massachusetts. The station opened on October 23, 1932 as a one-station extension of the Boylston Street ...

. ** The Union Square spur splits off from the

Green Line Extension The Green Line Extension (GLX) was a construction project to extend the Massachusetts Bay Transportation Authority (MBTA) Green Line light rail system northwest into Somerville and Medford, two inner suburbs of Boston, Massachusetts. The p ...

of the MBTA Green Line via an aerial flying junction on the Red Bridge viaduct in the Inner Belt area of

Somerville, Massachusetts Somerville ( ) is a city located directly to the northwest of Boston, and north of Cambridge, in Middlesex County, Massachusetts, United States. As of the 2020 United States Census, the city had a total population of 81,045 people. With an area o ...

just north of

Lechmere station Lechmere station is a Massachusetts Bay Transportation Authority (MBTA) Green Line light rail station in Lechmere Square in East Cambridge, Massachusetts. It is located on the east side of Monsignor O'Brien Highway near First Street, adjacen ...

in Cambridge. Lead tracks to the GLX maintenance facility also split off from the junction slightly further west. ** The two southern branches of the MBTA Red Line in Boston split via a flying junction just north of JFK/UMass station. In addition, lead tracks to Cabot Yard maintenance facilities branch off from the junction. *

Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...

, Illinois ** On the Chicago "L", where Orange Line trains diverge from Green Line trains north of 18th Street, as well as underground where a non-revenue flying junction separates Red Line trains heading to

95th 95 or 95th may refer to: * 95 (number) * one of the years 95 BC, AD 95, 1995, 2095, etc. * 95th Division (disambiguation) * 95th Regiment ** 95th Regiment of Foot (disambiguation) * 95th Squadron (disambiguation) * Atomic number 95: americium *M ...

from those heading to the South Side main line, currently used to send some rush-period Red Line trains to Ashland/63rd. **The Milwaukee–Dearborn subway (now part of the Blue Line) was constructed to have a flying junction where turning between Lake Street and Milwaukee Avenue at Canal Street. The outbound tunnel and its stub, designed to continue west under Lake Street, was bored at less depth than the inbound tunnel and its Lake Street stub, in order to allow future Lake Street trains (now part of the

Green Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 nm. In subtractive color systems, used in painting and color printing, it is created by a combi ...

and ( Pink Lines) to run under or over the opposing Milwaukee Avenue trains while entering or exiting the shared portion of the Lake Street tunnels. Plans in 1939 called for tunnels to replace the elevated Lake Street tracks east of approximately Racine Avenue. By 1962, the planned Lake Street tunnels to/from Racine Avenue would have curved south to Randolph Street and bypassed the Milwaukee-Lake-Dearborn tunnel entirely.Chicago Transit Board, ''Plan for Expanding Rapid Transit Service in the Central Area of Chicago'' (Chicago: Chicago Transit Board, April 20, 1962). ** Another flying junction is under construction immediately north of Belmont/Sheffield to increase capacity on the Red Line, Brown Line, and Purple Line Express. *

Denver Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the Unit ...

, Colorado ** On the

Regional Transportation District The Regional Transportation District, more commonly referred to as RTD, is the regional agency operating public transit services in eight out of the twelve counties in the Denver-Aurora-Boulder Combined Statistical Area in the U.S. state of Col ...

in Denver between the Southeast Corridor and the I-225 Corridor: the Southeast Corridor is on the west side of I-25 and the I-225 Corridor is in the median of I-225. The grade separations of the junction are woven into the grade separations of the interchange between the two highways. * New York, New York ** On the New York City Subway there is an above-ground example at Hammel's Wye on the

IND Rockaway Line The IND Rockaway Line is a rapid transit line of the IND Division of the New York City Subway, operating in Queens. It branches from the IND Fulton Street Line at Rockaway Boulevard, extending over the Jamaica Bay, into the Rockaways. The ...

, as well as numerous below-ground examples across the network ** Connecting Metro-North Railroad's

New Haven Line The Metro-North Railroad New Haven Line is a commuter rail line running from New Haven, Connecticut to New York City. It joins the Harlem Line at Mount Vernon, New York and continues south to Grand Central Terminal in Manhattan. The New Haven ...

and

Harlem Line The Metro-North Railroad Harlem Line, originally chartered as the New York and Harlem Railroad, is an commuter rail line running north from New York City to Wassaic, in eastern Dutchess County. The lower from Grand Central Terminal to Sou ...

, near

Wakefield Wakefield is a cathedral city in West Yorkshire, England located on the River Calder. The city had a population of 99,251 in the 2011 census.https://www.nomisweb.co.uk/census/2011/ks101ew Census 2011 table KS101EW Usual resident population, ...

station in the

Bronx The Bronx () is a borough of New York City, coextensive with Bronx County, in the state of New York. It is south of Westchester County; north and east of the New York City borough of Manhattan, across the Harlem River; and north of the New Y ...

Philadelphia Philadelphia, often called Philly, is the List of municipalities in Pennsylvania#Municipalities, largest city in the Commonwealth (U.S. state), Commonwealth of Pennsylvania, the List of United States cities by population, sixth-largest city i ...

, Pennsylvania ** Amtrak's

, where the Northeast Corridor meets the

and sorts into

's lower and upper level platforms. Also known as Zoo Interlocking, the name comes from the

Philadelphia Zoo The Philadelphia Zoo, located in the Centennial District of Philadelphia on the west bank of the Schuylkill River, is the first true zoo in the United States. It was chartered by the Commonwealth of Pennsylvania on March 21, 1859, but its openin ...

, which is located in the crescent shaped pocket between the junction and the river. ** On SEPTA's

Cynwyd Line The Cynwyd Line is a SEPTA Regional Rail line from Center City Philadelphia to Cynwyd in Montgomery County, Pennsylvania. Originally known as the Ivy Ridge Line, service was truncated on May 17, 1986, at its current terminus at Cynwyd. Trac ...

, diverging from the Keystone Corridor west of

52nd Street 52nd Street is a -long one-way street traveling west to east across Midtown Manhattan, New York City. A short section of it was known as the city's center of jazz performance from the 1930s to the 1950s. Jazz center Following the repeal of ...

. ** On SEPTA Airport Line, diverging from the Northeast Corridor south of Penn Medicine ** On SEPTA's subway–surface trolley lines, where the Route 10 diverges from Routes 11/13/34/36 west of 33rd Street. ** On SEPTA's

Broad Street subway The Broad Street Line (BSL), also known as the Broad Street subway (BSS), Orange Line, or Broad Line, is a subway line owned by the city of Philadelphia and operated by the Southeastern Pennsylvania Transportation Authority (SEPTA). The line r ...

, where Broad-Ridge Spur trains diverge at Fairmount. There are also provisions for flying junctions north of

Erie Erie (; ) is a city on the south shore of Lake Erie and the county seat of Erie County, Pennsylvania, United States. Erie is the fifth largest city in Pennsylvania and the largest city in Northwestern Pennsylvania with a population of 94,831 a ...

for the Roosevelt Boulevard Subway, and north of Olney for an extension on North Broad Street; both are maintained as layup tracks. *

San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...

, California ** The Oakland Wye, where all of Bay Area Rapid Transit's mainline operations converge near downtown Oakland ** On the

Market Street subway The Market Street subway is a two-level subway tunnel that carries Muni Metro and BART trains under Market Street in San Francisco, California.San Francisco San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...

where the J Church and

N Judah The N Judah is a hybrid light rail/streetcar line of the Muni Metro system in San Francisco, California. The line is named after Judah Street that it runs along for much of its length, named after railroad engineer Theodore Judah. It links downt ...

lines join the main line of the subway. The subway portal is east of the intersection of Church Street and Duboce Avenue in the

Duboce Triangle The Duboce Triangle is a neighborhood of San Francisco, California, located below Buena Vista Park and between the neighborhoods of the Castro/Eureka Valley, the Mission District, and the Lower Haight. According to the 2010 neighborhoods map of ...

neighborhood, immediately north of a

Safeway Safeway is an American supermarket chain founded by Marion Barton Skaggs in April 1915 in American Falls, Idaho. The chain provides grocery items, food and general merchandise and features a variety of specialty departments, such as bakery, d ...

supermarket and south of the San Francisco branch of the United States Mint. *

, District of Columbia ** All main-line connections on the Washington Metro – adjacent to the Pepco power plant on Benning Road (near the Stadium-Armory station) is a large three-track structure with a turnback pocket where the Blue, Silver and Orange Lines meet. This would have been part of the Oklahoma Avenue station, had it been built. South of the King Street station in Alexandria is a series of tunnels where the Blue and Yellow Lines meet. There are also flying junctions near three underground rail stations: Rosslyn (Blue, Silver, and Orange Lines), L'Enfant Plaza (Green and Yellow lines), and the Pentagon (Blue and Yellow lines).

Notes

References

External links

WikiMapia link – aerial photo of Fretin triangle (mentioned above)

Photo link – flying junction on Pennsylvania Railroad north of 30th Street Station, Philadelphia, Pennsylvania, United States

Photo link – simpler flying junction at terminus of Market–Frankford transit line, 69th Street Station, Philadelphia, Pennsylvania, United States
{{Railway track layouts Rail junction types Railway bridges

Complexity

Flying junction without crossings

High-speed rail

Examples

See also

Notes

References

External links