. The street railway review . s. No ducts are in the north wall. After the baseof the wall has been formed in place, the triple-duct vitrified pipesare set up in their proper positions and cemented together with amixture of one part cement to two parts of sand. The individualrows of ducts are separated by J-^-in. layers of this mixture. Theside of the ducts away from the subway is plastered with a layer of Si-iT. 15, STRKKT RAILWAY RKVIEW S21 lliis iciiuiil iiiisliin- \i\inu wliicli is apiilird lln- w;il<T|irci<iriii(;. I li-watii-pioofiMK (if llic side walls consists nf a (irst c
. The street railway review . s. No ducts are in the north wall. After the baseof the wall has been formed in place, the triple-duct vitrified pipesare set up in their proper positions and cemented together with amixture of one part cement to two parts of sand. The individualrows of ducts are separated by J-^-in. layers of this mixture. Theside of the ducts away from the subway is plastered with a layer of Si-iT. 15, STRKKT RAILWAY RKVIEW S21 lliis iciiuiil iiiisliin- \i\inu wliicli is apiilird lln- w;il<T|irci<iriii(;. I li-watii-pioofiMK (if llic side walls consists nf a (irst coat of Ccrionwatcr-proofiiiR followed by otic layer of Inirlap, tlicii a second coalof Cerion folliiweil hy a layer of burlap, then a third coat ofCcrion, inaliiriK in all tlircc coats of tli<! waterproofinK material.■mil lUM IS nf burlap. This waterproofing is carried up the oul-sidi of llie line of ducts to connect with the asphalt mastic water-proollnK in the roof of the subway, The tiers of <hKts in the south. CllNSTKfCTION OF CONCRETE ROOF AT 23RD ST. wall form the core of the structure from the elevation of the baseof the track rail to a height of about one foot below the roof sup-porting girders. This waterproofing compound called Cerion isa by-product obtained from the residuum in the process of refiningpetroleum. Outside of the waterproof covering for the cable ductsis a layer of concrete of the 1-3-6 mixture, 8 in. thick. The sidewalls are reinforced by horizontal S^-in. rods spaced 18 in. center tocenter, intersecting vertical rods i in. in diameter spaced 12 to center. Those portions of the norlh wall wliich are 3 ft. thick and carr>no cable conduits have no waterproof covering. The underdrainswill relieve the wall of the subway of any continued pressure fromwater in the sub-soil and it is therefore expected that the concretewall 3 ft. thick will not be affected by water from the outside. The duct chambers for the Keystone Telephone Cos. ca
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Keywords: ., book, bookcentury1800, bookdecade1890, booksubjectstreetrailroads
