Editing Independent Subway System (section)

===Proposed expansion===
{{main|Proposed New York City Subway expansion}}
Mayor John Hylan proposed some never-built lines in 1922 even before the first leg of the IND was completed. These lines included:<ref name="nycsubway.org"/>

*A West Side trunk line in Manhattan between 14th Street and the city limits at [[Yonkers, New York|Yonkers]]. The line would be 4 tracks between 14th Street and 162nd Street, 3 tracks to Dyckman Street, and 2 tracks to the terminal. There would be a two-track spur from 162nd Street to 190th Street via Amsterdam Avenue. From 14th Street, the line would split; two tracks would connect to the BMT Canarsie Line and two tracks would continue south to a loop at Battery Park and an East River tunnel to [[Atlantic Avenue (New York City)|Atlantic Avenue]] and Hicks Street, Brooklyn. Supposedly, there was also a plan of a line to [[Red Hook, Brooklyn|Red Hook]].
*A trunk line, 4 tracks, on [[First Avenue (Manhattan)|First Avenue]] from the Harlem River to 10th Street. From 10th Street, the line would split. Two tracks would run via [[Third Avenue]] and the [[Bowery]] to a new Lafayette Avenue subway in Brooklyn. The other two would run to a loop near City Hall. From the Harlem River, the line would run to [[East 161st Street|161st Street]], and split into two 3-track routes: one to Fordham Road & Southern Blvd and the other to Webster Ave. & Fordham Road, where it would join the current IRT White Plains Road line and continue to 241st Street. Since this portion of the IRT El was already built to BMT clearances, and Hylan's system would consider using BMT clearances as well, all that would have to be done along this section is shave back the platforms.
*A line from [[125th Street (Manhattan)|125th Street]] (near today's [[Henry Hudson Parkway]]) crosstown, to and across the [[East River]], to [[Astoria, Queens]], likely connecting to the [[BMT Astoria Line]].
*A new subway line, with between two and four tracks at various areas, from approximately the [[Hunters Point Avenue (IRT Flushing Line)|Hunters Point Avenue]] station on today's [[IRT Flushing Line]] in Queens, heading in a southeasterly direction to Lafayette Avenue, Brooklyn. At Lafayette Avenue, the line would split. Two tracks would turn into a four-track line along Lafayette Avenue. The other two tracks would run to Flatbush and Franklin Avenues.
*A 4-track subway line from Brooklyn's [[Borough Hall (Brooklyn)|Borough Hall]] via the Lafayette Avenue subway to [[Bedford Avenue]]. From there it was three tracks to [[Broadway (Brooklyn)|Broadway]] to [[Cypress Hills, Brooklyn]] where the line would continue on the present-day [[BMT Jamaica Line]]. (The line would have ended at [[168th Street (BMT Jamaica Line)|168th Street]], where the BMT Jamaica Line once ended.) The subway would have run directly under the line along Broadway giving it direct competition for passengers, and (in Hylan's opinion) draining revenues from the BMT. Two tracks of the Lafayette Avenue subway would connect with the proposed First Avenue line.
*A new branch off the [[IRT Eastern Parkway Line]] in Brooklyn onto [[Utica Avenue]], running under Utica to [[Flatlands Avenue]].
*A 4-track subway under Flatbush Avenue in Brooklyn to [[Nostrand Avenue]], to Emmons Avenue in Sheepshead Bay, turning west onto Emmons Avenue to Surf Avenue in [[Coney Island]]. A branch of this line would head out to [[Floyd Bennett Field]] under Flatbush Avenue.
*Extension of the [[BMT Canarsie Line]] to the BMT Jamaica Line somewhere beyond 121st Street in Queens.
*A new line running from Prospect Avenue via Fort Hamilton Parkway, to 10th Avenue, terminating at 90th Street. [[BMT Culver Line]] trains would use this line.
*Extension of the [[BMT Fourth Avenue Line]] in Brooklyn, south to [[Bay Ridge – 95th Street (BMT Fourth Avenue Line)|Bay Ridge – 95th Street]]. (This was the only other line that was complete.)
*Extension of the BMT Fourth Avenue Line east to the Fort Hamilton Parkway Line and the [[BMT West End Line]].
*A two-track line from the BMT Fourth Avenue Line at 67th Street to Staten Island via the [[Staten Island Tunnel]].
*Extension of the [[IRT New Lots Line]] from New Lots Avenue to Lefferts Boulevard.
*Extension of the IRT Flushing Line to Bell Boulevard in [[Bayside, Queens|Bayside]] via [[Main Street (Queens)|Main Street]], [[Kissena Boulevard]], and [[Northern Boulevard]].
*A branch off the IRT Flushing Line to Jamaica from [[Roosevelt Avenue]].<ref name="nycsubway.org"/>

A major expansion of the IND was first planned in 1929.<ref name="ind second system">nycsubway.org – [http://nycsubway.org/ind/indsecond.html IND Second System]</ref> It would have added over 100 miles of new routes in Manhattan, Brooklyn, Queens, and the Bronx, merging with, intersecting or extending the existing IND rights-of way. It was claimed that this expansion, combined with the operating IRT, BMT, and IND lines, would provide subway service within a half mile of anyone's doorstep within these four boroughs.<ref name="ind second system"/> Pricing – excluding acquisition and equipment costs – was estimated at [[United States dollar|US$]]438 million. The entire first phase had only cost US$338 million, ''including'' acquisition and equipment costs.<ref name="ind second system"/>

Not long after these plans were unveiled, the [[Wall Street Crash of 1929]] occurred and the [[Great Depression]] was ushered in, and the plans essentially became history overnight.<ref name="ind second system"/> Various forms of the expansion resurfaced in 1939,<ref name="nycsubway.org"/> 1940,<ref>[http://1.bp.blogspot.com/-HDTTMT-jAHs/T5_WEPEViiI/AAAAAAAAAMw/F9yGC2LHtD8/s1600/76st_b.jpg Track diagram of planned underground Fulton Street Line extension in Queens]</ref> 1951,<ref>{{cite web |url=http://www.thejoekorner.com/bdtrans-51/bd-trans-51-plan-indx.html |title=Board of Transportation – 1951 |publisher=Thejoekorner.com |access-date=March 25, 2014 |archive-date=February 24, 2021 |archive-url=https://web.archive.org/web/20210224152538/http://www.thejoekorner.com/bdtrans-51/bd-trans-51-plan-indx.html |url-status=dead }}</ref> [[Program for Action|1968]],<ref>{{cite web|url=http://secondavenuesagas.com/wp-content/uploads/2008/06/1968expansionlarge.jpg|title=1968 NYCTA Expansion Plans (Picture)|publisher=Second Avenue Sagas|access-date= April 15, 2014}}</ref><ref>[http://www.thejoekorner.com/lines/progforaction.htm Program for Action maps] from thejoekorner.com</ref> and 1998<ref>{{cite web |url=http://www.qgazette.com/news/2007-06-27/Features/Flashback_To_1999_001.html |title=Flashback To 1999 &#124; www.qgazette.com &#124; Queens Gazette |publisher=www.qgazette.com |date=June 27, 2007 |access-date=March 25, 2014 |archive-url=https://web.archive.org/web/20160322134801/http://www.qgazette.com/news/2007-06-27/features/flashback_to_1999_001.html |archive-date=March 22, 2016 |url-status=dead }}</ref> but were never realized. This was the time when the IND had planned widespread elevated construction.<ref name="nycsubway.org"/>

The [[Second Avenue Subway]], one of the main parts of the plan, is open between 63rd and 96th Streets as of January 1, 2017.