Editing Washington Monument (section)

===Stairs and elevator===
[[File:Sections - Washington Monument, High ground West of Fifteenth Street, Northwest, between Independence and Constitution Avenues, Washington, District of Columbia, DC HABS DC,WASH,2- (sheet 31 of 37).png|thumb|right|upright=1|North interior wall with its stairs and their wire screening]]
The monument is filled with ironwork, consisting of its stairs, elevator columns and associated tie beams, none of which supports the weight of the stonework. It was redesigned in 1958 to reduce congestion and improve the flow of visitors. Originally, visitors entered and exited the west side of the elevator on the observation floor, causing congestion. So the large landing at the 490-foot level was expanded to a full floor and the original spiral stair in the northeast corner between the {{convert|490|and|500|foot|m|1|adj=on}}  levels was replaced by two spiral stairs in the northeast and southeast corners. Now visitors exit the elevator on the observation floor, then walk down either spiral stair before reboarding the elevator for their trip back down.<ref name=HSR/>{{rp|fig 3.31}}

The main stairs spiral up the interior walls from the entry lobby floor to the elevator reboarding floor at the {{convert|490|foot|m|adj=on}} level. The elevator occupies the center of the shaft well from the entry lobby to the observation floor, with an elevator machine room (installed 1925–26) whose floor is {{convert|18|ft|10|in|m|2}} above the observation floor and an elevator pit (excavated 1879) whose floor is {{convert|9|ft|m|2}} <!-- 7'10" + 14+1/8" --> below the entry lobby floor.<ref name=HABSdrawings/>{{rp|sheet 31–35}}<ref name=Torres/>{{rp|61, 74}} The stairs and elevator are supported by four wrought iron columns each. The four supporting the stairs extend from the entry lobby floor to the observation floor and were set at the corners of a {{convert|15|ft|8|in|m|2|adj=on}} square. The four supporting the elevator extend from the floor of the elevator pit to {{convert|14|ft|m|1}} above the observation floor and were set at the corners of a {{convert|9|ft|9+1/2|in|m|1|adj=on}} square.<ref name=HSR/>{{rp|3{{hyphen}}6}}<!-- hyphenated page is one page, not a range, because book uses page within chapter numbering --> The weight of the ironwork is {{convert|275|LT|ST t|0|abbr=off}}.<ref name=Casey1884/> [[Cast iron]], [[wrought iron]], and steel were all used. The two small spiral stairs installed in 1958 are aluminum.<ref name=HSR/>

Most landings occupy the entire east and west interior walls every {{convert|10|ft|m|2}} from and including the east landing at the {{convert|30|foot|m|1|adj=on}} level up to the west landing at the {{convert|480|foot|m|adj=on}} level, east then west alternately. Three stairs with small landings rise from the entry lobby floor to the {{convert|30|foot|m|1|adj=on}} level successively along the north, west and south interior walls. Landings from the {{convert|30|foot|m}} level up to the {{convert|150|foot|m}} level are {{convert|3|ft|2+1/4|in|m|2}} by {{convert|25|ft|1|in|m|2}}, while landings from the {{convert|160|foot|m|adj=on}} level to the {{convert|480|foot|m|adj=on}} level are {{convert|7|ft|10+3/4|in|m|2}} by {{convert|31|ft|5+1/2|in|m|2}}. All stairs are on the north and south walls except for the aforementioned west stair between the {{convert|10-20|foot|m|2|adj=on}} levels, and the two spiral stairs.<ref name=HSR/>

About one fourth of visitors chose to ascend the monument using the stairs when they were available. They were closed to up traffic in 1971, and then closed to all traffic except by special arrangement in 1976.<ref name=HSR/>{{rp|3{{hyphen}}18}}<!-- hyphenated page is one page, not a range, because book uses page within chapter numbering --><ref name=Torres/>{{rp|101}} The stairs had 898 steps until 1958, consisting of 18 [[stair riser|riser]]s in each of the 49 main stairs plus 16 risers in the spiral stair.<ref name=Olszewski/>{{rp|chp 7}}<ref name=Snell/>{{rp|18}} Since 1958 the stairs have had 897 risers if only one spiral stair is counted because both spiral stairs now have 15 risers each.<ref name=HABSdrawings/>{{rp|sheets 6, 31–35}}<ref name=Torres/>{{rp|72}} These figures do not include two additional steps in the entry passage that were covered up in 1975 by a ramp and its inward horizontal extension to meet the higher (since 1886) entry lobby floor. One step was {{convert|3.2|ft|m|0}} away from the outer walls and the other was at the end of the passage, {{convert|15|ft|m|1}} away from the outer walls.<ref name=HSR/>{{rp|3{{hyphen}}17{{ndash}}3{{hyphen}}18, figs 3.11, 3.32{{ndash}}3.33, 3.39}}<!-- page within chapter numbering -->

As initially constructed, the interior was relatively open with two-rail [[handrail]]s, but a couple of suicides and an accidental fall prompted the addition of tall wire screening {{convert|7|ft|m|1}} high with a large diamond mesh) on the inside edge of the stairs and landings in 1929. The original steam powered elevator, which took 10 to 12 minutes to ascend to the observation floor, was replaced by an electric elevator powered by an on-site [[dynamo]] in 1901 which took five minutes to ascend. The monument was connected to the [[electrical grid]] in 1923, allowing the installation of a modern electric elevator in 1925–26 which took 70 seconds. The latter was replaced in 1958 and again in 1998 by 70-second elevators.<ref name=HSR/>{{rp|2{{hyphen}}13, 2{{hyphen}}15, 3{{hyphen}}20{{ndash}}3{{hyphen}}21, B{{hyphen}}44, B{{hyphen}}47, B{{hyphen}}48}}<!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering --><ref name=Harvey/>{{rp|102, 107–8}} From 1997 to 2000, the wire screening at three platforms was replaced by large glass panels to allow visitors on the elevator to view three clusters of memorial stones that were synchronously lit as the elevator automatically slowed while passing them during its descent.<ref name=HSR/>{{rp|3{{hyphen}}21, 4{{hyphen}}16}}<!-- each hyphenated page is one page, not a range, because book uses page within chapter numbering -->
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