Editing IND Culver Line (section)

===Jay Street to Church Avenue===
[[Image:Jay Street Borough Hall Subway Station by David Shankbone.jpg|thumb|225px|[[Jay Street – MetroTech (IND Culver Line)|Jay Street – MetroTech]]]]
The subway portion of the IND Culver Line was originally designated the '''Brooklyn Line''' but has also been called the '''Smith Street Line''',<ref name="Raskin-RoutesNotTaken-2013" /><ref>[http://www.subwaywebnews.com/Photo%20Archive/Jaystation.jpg Photo of Jay Station (SubwayNews.com)] {{webarchive|url=https://web.archive.org/web/20051203013610/http://www.subwaywebnews.com/Photo%20Archive/Jaystation.jpg |date=December 3, 2005}}</ref> '''Church Avenue Line''', '''South Brooklyn Line''', and various other names. The express tracks beneath [[Prospect Park (Brooklyn)|Prospect Park]] are sometimes referred to as the '''Prospect Park Line'''.<ref name="NYTimes-CulverRecapture-1932" />

The line begins at the four-tracked [[Jay Street–MetroTech (New York City Subway)|Jay Street–MetroTech]] station, where the [[IND Sixth Avenue Line|IND Sixth Avenue]] and [[IND Eighth Avenue Line|Eighth Avenue]] lines interchange and continue as the Culver and [[IND Fulton Street Line|Fulton Street]] lines respectively.<ref name="tracks" /><ref name="MTA-FExpStudy-May2016" /> Running under Smith Street south of the station, the Culver tracks split into local and express tracks, with the two express tracks ramping down to the lower level of [[Bergen Street (IND Culver Line)|Bergen Street]], while the local tracks merge with the [[IND Crosstown Line]] tracks from [[Hoyt-Schermerhorn Street (IND Fulton Street Line station)|Hoyt-Schermerhorn Street]] before entering the upper level.<ref name="tracks" /><ref name="MTA-FExpStudy-May2016" /><ref name="MTA-CulverRehabPresentCB6-2007" /> Between Jay Street and Bergen Street, the line passes under both the [[IRT Eastern Parkway Line]] and the Fulton Line tracks curving east into Hoyt-Schermerhorn Street, requiring a deeper tunnel and extensive ventilation systems.<ref name="BklynEagle-INDBergen-Mar121933">{{cite news|title=City's Subway Open March 20 To Bergen St.|url=https://bklyn.newspapers.com/image/59887096/?terms=%22bergen%22%2B%22independent%2Bsubway%22|access-date=July 4, 2016|work=[[Brooklyn Daily Eagle]]|via=[[Newspapers.com]]|date=March 12, 1933|page=8|archive-date=August 4, 2020|archive-url=https://web.archive.org/web/20200804003117/https://bklyn.newspapers.com/image/59887096/?terms=%22bergen%22%2B%22independent%2Bsubway%22|url-status=live}}</ref>

At Carroll Street, the express tracks ramp up to rejoin the local tracks, and all four tracks rise onto the Culver Viaduct, curving onto Ninth Street.<ref name="tracks" /><ref name="MTA-FExpStudy-May2016" /><ref name="MTA-CulverRehabPresentCB6-2007" /> East of Fourth Avenue station towards Park Slope, the tracks become a subway once again. Past 7th Avenue, the local tracks diverge, curving south to 15th Street and Prospect Park West, while the express tracks take a direct route beneath [[Prospect Park (Brooklyn)|Prospect Park]]. This is one of two places in the subway where the express tracks diverge from the local tracks, the other being on the [[IND Queens Boulevard Line]] between 65th Street and 36th Street.<ref name="tracks" /><ref name="MTA-FExpStudy-May2016" /><ref name="MTA-CulverRehabPresentCB6-2007" /><ref name="NYTimes-OurGreatSubway-IND2ndSystem-1929" /><ref name="IND2ndSystem1929Map">[[:File:1929 IND Second System.jpg|Board of Transportation of the City of New York Engineering Department, Proposed Additional Rapid Transit Lines And Proposed Vehicular Tunnel]], dated August 23, 1929</ref><ref name="IND2ndSystem1939Map" /><ref name="BklynStandard-INDFultonCulver-Nov1927" /> The express tracks rejoin the right-of-way at approximately Terrace Place and Prospect Avenue,<ref name="BklynStandard-INDFultonCulver-Nov1927" /> running on a lower level under Prospect Avenue and Fort Hamilton Parkway near the Prospect Park Parade Grounds, then rise up as the line curves onto [[McDonald Avenue]]. The line then parallels the route of the original Culver Line surface railroad into [[Church Avenue (IND Culver Line)|Church Avenue]] station, the last stop of the original IND service.<ref name="tracks" /><ref name="MTA-FExpStudy-May2016" /><ref name="NYTimes-OurGreatSubway-IND2ndSystem-1929" />

A single track in both directions, connecting from the local and express tracks in each direction, then ramps down to the four-track [[Church Avenue Yard]], used as a relay and storage facility for {{NYCS|G}} trains.<ref name="tracks" /><ref name="MTA-FExpStudy-May2016" /><ref name="MTA-GLineReview-2013" /><ref name="MTA-CulverRehabPresentCB6-2007" /><ref name="MTA-GLineReview-Append-2013">{{cite web |title=Review of the G Line: Appendices |url=http://web.mta.info/nyct/service/G_Appendices_7_10_13.pdf |publisher=[[Metropolitan Transportation Authority]] |access-date=October 28, 2015 |date=July 10, 2013 |archive-date=January 27, 2016 |archive-url=https://web.archive.org/web/20160127233038/http://web.mta.info/nyct/service/G_Appendices_7_10_13.pdf |url-status=live}}</ref><ref>{{cite web |title=Hollywood Underground: The Art of Making Movies in The New York City Subway |url=http://web.mta.info/nyct/sub_filming/underground.htm |publisher=[[Metropolitan Transportation Authority]] |access-date=August 16, 2015 |archive-date=August 31, 2015 |archive-url=https://web.archive.org/web/20150831025122/http://web.mta.info/nyct/sub_filming/underground.htm |url-status=live}}</ref> The four mainline tracks ascend to the [[Culver Ramp]] on McDonald Avenue between Cortelyou Road and Avenue C, which connects the subway portion of the IND Culver Line with the former BMT Culver Line elevated structure. Despite being a part of the IND Division, the Culver elevated portion is controlled by BMT radio dispatch, so train operators change between the IND (B-2) and BMT (B-1) radio frequencies at this point.<ref name="tracks" />

====Culver Viaduct====
[[File:NYCS IND Culver GowanusCanalBridge.jpg|thumb|200px|The Culver Viaduct spans the [[Gowanus Canal]].]]
The northern section of the Culver Line is a four-track line, entirely underground except for [[Smith–Ninth Streets (IND Culver Line)|Smith–Ninth Streets]] and [[Fourth Avenue (IND Culver Line)|Fourth Avenue]] stations.<ref name="tracks" /> The two stations sit on a massive one-mile long<ref name="MTA-CulverRehabPresentCB6-2007" /> steel and concrete [[viaduct]] which spans the [[Gowanus Canal]] between 9th and 10th Streets. This structure is now referred to as the '''Culver Viaduct''' or '''Culver Line Viaduct''',<ref name="MTA-FLineReview-2009" /><ref name="MTA-GLineReview-2013" /> the only portion of the original IND subway to be elevated, and the only section other than the now-demolished [[IND World's Fair Line|World's Fair Railroad]] to be outdoors.<ref name="gay" /><ref>{{Cite web |url=http://forgotten-ny.com/2004/06/crazy-train-some-of-the-more-unusual-subway-stations/ |title=Crazy Train: NYC's Weirdest Subway Stations |date=June 20, 2004 |access-date=August 23, 2015 |archive-date=September 7, 2015 |archive-url=https://web.archive.org/web/20150907185802/http://forgotten-ny.com/2004/06/crazy-train-some-of-the-more-unusual-subway-stations/ |url-status=live}}</ref> The viaduct was constructed due to the depth of the canal (15 feet at its deepest point),<ref name="gay" /><ref name="NYTimes-INDCulver-Gowanus-1927" /><ref>{{cite web |title=Gowanus Canal Superfund Site: Kings County, New York |url=http://www3.epa.gov/region02/superfund/npl/gowanus/pdf/gowanus_prap.pdf |publisher=[[United States Environmental Protection Agency]] |access-date=November 7, 2015 |date=December 2012 |archive-date=November 23, 2015 |archive-url=https://web.archive.org/web/20151123211941/http://www3.epa.gov/region02/superfund/npl/gowanus/pdf/gowanus_prap.pdf |url-status=live}}</ref> due to the topography of the Park Slope neighborhood,<ref name="gay" /><ref name="NYTimes-INDCulver-Gowanus-1927" /> and to avoid local stores in the area.<ref name="BklynStandard-INDFultonCulver-Nov1927" /> Otherwise, a tunnel carrying the line would have to have been built below both the canal and the [[BMT Fourth Avenue Line]] (necessitating stations deep below the ground); or Ninth Street would be raised above grade level to pass over the canal and BMT subway.<ref name="NYTimes-INDCulver-Gowanus-1927" />

Both underground options were considered expensive and impractical, and the viaduct was estimated to save $12 million in construction costs when it was selected in 1927.<ref name="NYTimes-INDCulver-Gowanus-1927" /> During planning, the viaduct's height was later increased from {{convert|60|ft|m}}<ref name="NYTimes-INDCulver-Gowanus-1927" /> to around {{convert|90|ft|m}}, due to now-defunct navigation regulations for tall-mast shipping.<ref name="BklynStandard-INDFultonCulver-Nov1927">{{cite news|title=Subway Dirt Will Start to Fly Here Soon: Board Indicates Private Property to Be Taken in Cranberry Street.|url=http://fultonhistory.com/highlighter/highlight-for-xml?altUrl=http%3A%2F%2Ffultonhistory.com%2FNewspaper%252014%2FBrooklyn%2520NY%2520Standard%2520Union%2FBrooklyn%2520NY%2520Standard%2520Union%25201927%2FBrooklyn%2520NY%2520Standard%2520Union%25201927%2520-%25206908.pdf&highlightsFile=http%3A%2F%2Fwww.fultonhistory.com%2Fhighlighter%2Fhits%2F5f6e489edcc6e30d125ab8598d3f4e05#page=1|access-date=June 30, 2016|work=[[Brooklyn Standard Union]]|agency=[[Fultonhistory.com]]|date=November 10, 1927|page=2}}</ref><ref name="gay" /><ref>{{cite news |title=Gowanus Bridge Discussed; Concerns Along Canal Object to Fixed Span at Army Hearing |url=https://timesmachine.nytimes.com/timesmachine/1927/09/23/118646473.pdf |newspaper=[[The New York Times]] |access-date=November 7, 2015 |date=September 23, 1927 |archive-date=October 6, 2022 |archive-url=https://web.archive.org/web/20221006132645/https://timesmachine.nytimes.com/timesmachine/1927/09/23/118646473.html?pdf_redirect=true&site=false |url-status=live}}</ref> Because of this, Smith–Ninth Streets was built at an elevation of {{convert|87.5|ft|m}}, the highest subway station above ground level in the world.<ref name="MTA-FLineReview-2009" /><ref>{{Cite web |url=http://www.mta.info/news/stories/?story=177 |title=Rebuilding the Culver Viaduct |access-date=August 23, 2015 |archive-date=September 25, 2012 |archive-url=https://web.archive.org/web/20120925005121/http://www.mta.info/news/stories/?story=177 |url-status=live}}</ref><ref>Brooklyn!!, Summer 2013 issue, p.7, caption on photo from station reopening celebration, www.brooklyn-usa.org</ref> Fourth Avenue, meanwhile, is actually at a lower elevation and altitude than the Seventh Avenue underground station.

For most of its history, G service has terminated at Smith–Ninth Streets, relaying using the express tracks and switches at Fourth Avenue.<ref name="tracks" /> This occasionally caused delays to F service, and prevented express service from being operated.<ref name="MTA-FLineReview-2009" /><ref name="MTA-GLineReview-2013" /><ref name="MTA-CulverRehabPresentCB6-2007">{{cite web |title=Culver Line Rehabilitation: Presentation to Community Board 6 Transportation Committee – November 15, 2007 |url=http://cdn-sas.secondavenuesagas.com/wp-content/uploads/Culver%20Presentation.pdf |website=secondavenusagas.com |publisher=[[Metropolitan Transportation Authority]] |access-date=September 7, 2015 |archive-url=https://web.archive.org/web/20150907045743/http://cdn-sas.secondavenuesagas.com/wp-content/uploads/Culver%20Presentation.pdf |archive-date=September 7, 2015 |date=November 15, 2007 |url-status=dead}}</ref> In 2009, the G's terminus was moved to Church Avenue in order to complete renovations on the viaduct.<ref name="MTA-FLineReview-2009" /><ref name="MTA-GLineReview-2013" /> In July 2012, the G extension was made permanent.<ref name="MTA-GLineReview-2013" /><ref>{{Cite news|url=http://www.brooklynpaper.com/stories/35/29/dtg_gtrainsaved_2012_07_27_bk.html|title=G wiz! MTA plans to save the G train extension!|last=O'Neill|first=Natalie|date=July 19, 2012|newspaper=[[The Brooklyn Paper]]|access-date=July 21, 2012|archive-date=September 17, 2012|archive-url=https://web.archive.org/web/20120917053417/http://brooklynpaper.com/stories/35/29/dtg_gtrainsaved_2012_07_27_bk.html|url-status=live}}</ref>