Historical clue formulations

• Original N.Y.C. subway line — 2026-07-23
• Original N.Y.C. subway line — 2024-12-26
• N.Y.C. subway inits. — 2022-06-26
• N.Y.C.'s first subway line — 2022-02-11
• Old N.Y.C. subway inits. — 2021-03-14
• N.Y.C.'s first subway line — 2020-09-06
• N.Y.C.'s first subway line — 2020-06-28
• Original N.Y.C. subway line — 2019-10-27
• Old N.Y.C. depot inits. — 2019-05-10
• Original N.Y.C. subway line — 2019-03-26
• N.Y.C. subway letters — 2019-02-06
• N.Y.C. subway line — 2019-01-09
• N.Y.C. subway inits. — 2018-10-01
• N.Y.C. subway inits. — 2016-04-26
• N.Y.C. line — 2015-10-18
• Big Apple subway line — 2015-06-18
• N.Y.C. subway line — 2015-04-28
• N.Y.C.'s first subway co. — 2014-10-19
• N.Y.C. subway inits. — 2014-07-06
• N.Y.C. line — 2014-01-01
• Line to Wall Street, for short — 2013-06-21
• N.Y.C. line — 2013-05-24
• N.Y.C. line — 2013-03-30
• N.Y.C. line to the Bronx — 2013-03-23
• Bygone operator of N.Y.C.'s Second Avenue El — 2012-09-15
• N.Y.C.'s first subway line — 2012-08-29
• N.Y.C.'s first subway — 2012-06-13
• N.Y.C. commuting debut of 1904 — 2012-03-24
• First subway line in N.Y.C. — 2012-02-16
• N.Y.C. subway — 2011-10-21
• N.Y.C. subway inits. — 2011-10-14
• Old N.Y.C. elevated operator — 2010-11-12
• N.Y.C. subway line — 2010-10-24
• Operator of the original N.Y.C. subway — 2010-08-15
• New York subway inits. — 2010-08-08
• Subway line to Columbia U. — 2010-05-09
• N.Y.C. transportation debut of 1904 — 2010-01-01
• Original N.Y.C. subway line — 2009-11-10
• N.Y.C.'s original subway line — 2009-10-13
• N.Y.C. subway syst. — 2009-08-09
• N.Y.C. subway line — 2009-07-05
• N.Y.C. subway line — 2007-03-11
• N.Y.C. subway — 2006-10-27
• N.Y.C. subway — 2006-05-23
• N.Y.C. subway line — 2006-03-04
• N.Y.C. subway line — 2005-11-13
• N.Y.C. subway — 2005-01-30
• N.Y.C.'s first subway line — 2005-01-16
• N.Y.C. subway — 2004-05-21
• N.Y.C. subway line — 2004-03-31