Editing Hell Gate Bridge (section)

==== Arch and deck ====
The main span measures {{convert|1017|ft}} long between the outer faces of the masonry "towers" on either side of Hell Gate.<ref name="p1114484502" /><ref name="Greenstein p. 50" /><ref name="Ammann p. 1651" /> The clear span (between the inner faces) is {{convert|977.5|ft}},<ref name="Greenstein p. 50" /><ref name="p235664917" /> while the distance between the centers of these towers is {{convert|995|ft}}.<ref name="Ammann p. 1651" /> At the center of the main span, the deck reaches its maximum height, {{Convert|145|ft}} above mean high water,<ref name="RAG1914 p. 1368" /> with a clearance below of {{Convert|135|ft}}.<ref name="RAG1914 p. 891" /><ref name="Ammann p. 1661">{{harvnb|Ammann|1918|ps=.|page=1661}}</ref> The main span was intended to carry a total load of approximately 76,000 pounds per lineal foot, or {{convert|76000|lb/ft|kg/m|abbr=values|disp=out}} kilograms per lineal meter.<ref name="p235664917" /> The span uses high-[[carbon steel]] because it was cheaper than [[nickel steel]] at the time of construction.<ref name="Hill Sinclair 1922 p. 12">{{cite book |last1=Hill |first1=J.A. |url=https://books.google.com/books?id=RZQjAAAAMAAJ&pg=PA12 |title=Railway and Locomotive Engineering ... |last2=Sinclair |first2=A. |publisher=Angus Sinclair Company |year=1922 |page=12 |issue=v. 35 |access-date=March 8, 2024 |archive-date=March 8, 2024 |archive-url=https://web.archive.org/web/20240308225306/https://books.google.com/books?id=RZQjAAAAMAAJ&pg=PA12 |url-status=live}}</ref> In total, the main span required between {{convert|18000|and|20000|ST|}} of [[rolled steel]].<ref name="In 2024 q032" /><ref name="p502726608" /><ref name="nyt-1915-08-01" />

The span is a [[Hinged arch bridge|two-hinged arch]]; there are [[hinge]]s at the springing points of the arch (at the bases of the towers on either side of Hell Gate).<ref name="In 2024 q032" /><ref name="RAG1915 p. 424" /><ref name="p235664917" /> The arch's beams run along the north and south sides of a {{Convert|60|ft|4=-wide|adj=mid}} deck.<ref name="RAG1914 p. 890" /><ref name="Ammann p. 1678">{{harvnb|Ammann|1918|ps=.|page=1678}}</ref> On either side of the deck is an upper chord, with an inverted U-shaped cross section, and a lower chord, with a box-shaped cross section.<ref name="RAG1914 pp. 890–891">{{harvnb|Railway Age Gazette|1914|ps=.|pages=890–891}}</ref> The two chords are {{Convert|140|ft}} apart at either shore of Hell Gate, narrowing to {{Convert|40|ft}} apart at the middle of the river.<ref name="RAG1914 p. 890" /><ref name="Ammann p. 1678" /> Each lower chord ranges in thickness from approximately {{convert|7|to|11|ft}},<ref name="p235664917" /><ref name="RAG1914 pp. 890–891" /> and the thickest sections of the lower chord are divided into two compartments.<ref name="n142439586" /><ref name="RAG1915 p. 423">{{harvnb|Railway Age Gazette|1915|ps=.|page=423}}</ref> The upper chord is thinner and functions like a stiffening truss;<ref name="p235664917" /> it is shaped like a hump,<ref name="Thrall Billington 2008 p. 7" /><ref name="n142388040" /> both for structural reinforcement and for esthetic purposes.<ref name="Thrall Billington 2008 p. 7" /> It reaches a maximum height of {{Convert|300|ft}}<ref name="p509758823">{{cite news |date=January 2, 1917 |title=Bridge to Be Opened Soon at Hell Gate: It Completes a Continuous All Rail Route From Nova Scotia via New York to the South and West—has Four Tracks |work=The Christian Science Monitor |page=6 |issn=0882-7729 |id={{ProQuest|509758823}}}}</ref> or {{Convert|305|ft}} above mean high water.<ref name="In 2024 q032" /><ref name="Ammann p. 1651" /><ref name="Ammann pp. 1677–1678">{{harvnb|Ammann|1918|ps=.|pages=1677–1678}}</ref> Beams run vertically and diagonally between the upper and lower chords.<ref name="RAG1915 p. 424" /><ref name="Ammann p. 1678" /> There is also transverse bracing between the upper chords and lower chords on either side of the bridge.<ref name="Ammann p. 1679">{{harvnb|Ammann|1918|ps=.|page=1679}}</ref>

Eight stringers, or [[girder]]s, run parallel to and under the tracks for the entire length of the deck. Four additional stringers were intended to support unbuilt walkways or trolley tracks on either side.<ref name="RAG1915 p. 423" /><ref name="Ammann p. 1679" /> These are intersected by 24 transverse floor beams. Sixteen of the transverse beams are suspended from the lower chord, while the other eight beams are riveted to the vertical trusses between the lower and upper chords.<ref name="RAG1915 p. 423" /> Additional girders are used to stabilize the floor of the deck.<ref name="Ammann pp. 1679–1680">{{harvnb|Ammann|1918|ps=.|pages=1679–1680}}</ref>