Editing Grand Central Terminal (section)

=== Basement spaces ===
Grand Central Terminal's {{convert|48|acre|ha|adj=on}} basements are among the largest in the city.<ref name="untapped 20130313" /> Basement spaces include M42, which has [[Rectifier|AC-to-DC converters]] to power the track's [[third rail]]s,<ref name="IEEE-PES" /><ref name="RN p. 157" /> as well as Carey's Hole, a former retail storage space and present-day employee lounge and dormitory.<ref name=Careys-Hole-2010/>

==== Power and heating plants ====
[[File:GCT M42 Basement-Rotary-Untapped New York-Michelle Young.jpg|thumb|alt=A large piece of electrical equipment in the terminal basement|[[Rotary converter]] relics in the [[M42 (sub-basement)|M42 basement]]]]
Grand Central Terminal contains an underground [[sub-basement]] known as [[M42 (sub-basement)|M42]]. Its [[electrical substation]] is divided into substation 1T, which provides {{Convert|16,500|kW|}} for third-rail power, and substation 1L, which provides {{Convert|8000|kW|}} for other lighting and power.<ref name="IEEE-PES" /> The substation—the world's largest at the time—was built about {{Convert|100|ft|m}} under the Graybar Building at a cost of $3 million, and opened February 16, 1930.<ref name="IEEE-PES" /><ref>{{cite news|url=https://www.nytimes.com/1930/02/16/archives/huge-power-plant-100-feet-under-city-biggest-substation-in-world.html|title=Huge Power Plant 100 Feet Under City – Biggest Substation in World Moved Into Bedrock Under Grand Central Terminal – Service Never Cut Off – $3,000,000 System Ran Trains While Being Moved to Make Way for New Waldorf|date=February 16, 1930|website=The New York Times |issn=0362-4331|access-date=December 26, 2018|archive-date=December 27, 2018|archive-url=https://web.archive.org/web/20181227084742/https://www.nytimes.com/1930/02/16/archives/huge-power-plant-100-feet-under-city-biggest-substation-in-world.html|url-status=live}}</ref> It occupies a four-story space with an area of {{Convert|250|by|50|ft|m}}.<ref name="IEEE-PES" /><ref name="RN p. 157" />

====Carey's Hole====
[[File:Carey's Hole.jpg|thumb|upright=1.2|alt=Diagram showing rooms and track in the terminal|1913 map showing the space beneath Carey's barbershop]]
Another part of the basement is known as Carey's Hole. The two-story section is directly beneath the Shuttle Passage and adjacent spaces. In 1913, when the terminal opened, J. P. Carey opened a barbershop adjacent to and one level below the terminal's waiting room (now Vanderbilt Hall). Carey's business expanded to include a laundry service, shoe store, and [[haberdashery]]. In 1921, Carey also ran a limousine service using [[Packard]] cars, and in the 1930s, he added regular car and bus service to the city's airports as they opened. Carey would store his merchandise in an unfinished, underground area of the terminal, which railroad employees and maintenance staff began calling "Carey's Hole". The name has remained even as the space has been used for different purposes, including currently as a lounge and dormitory for railroad employees.<ref name=Careys-Hole-2010>{{cite web|title=General Engineering Consulting Feasibility Study for Redevelopment of Carey's Hole: Section 1: History of Carey's Hole|work=Beyer Blinder Belle|url=https://grandcentralterminal.app.box.com/s/z2mlivbdgn/file/750852164|date=November 29, 2010|access-date=January 20, 2018|archive-date=April 22, 2020|archive-url=https://web.archive.org/web/20200422165247/https://grandcentralterminal.app.box.com/s/z2mlivbdgn/file/750852164|url-status=live}}</ref>