Scientific American Volume 78 Number 03 (January 1898) . tly aboutthe pile, giving it thenecessary frictionalresistance and bear-ing power. It wasnot necessary tobuild any temporaryplatform for cuttingoff the piles. Thiswas done when theylay on the gridironbefore the driving, anark on the hammerserving to indicateduring the sinkingwhen the proper level had been reached. The driver was then swunground again to the tender, and a cap was picked up,brought round to the front, laid in place and drift-bolted, similar operations being gone through in layingthe stringers and rails. After a certain len
Scientific American Volume 78 Number 03 (January 1898) . tly aboutthe pile, giving it thenecessary frictionalresistance and bear-ing power. It wasnot necessary tobuild any temporaryplatform for cuttingoff the piles. Thiswas done when theylay on the gridironbefore the driving, anark on the hammerserving to indicateduring the sinkingwhen the proper level had been reached. The driver was then swunground again to the tender, and a cap was picked up,brought round to the front, laid in place and drift-bolted, similar operations being gone through in layingthe stringers and rails. After a certain length of trestle had been completed,the brush mattresses or fascines were built and sunk to the bottom. The object of the mattresses was toform a foundation for the rock, hold it together andprevent it from sinking piecemeal into the sand. Theywere laid in two long strips, each 20 feet wide, one be-neath the trestle and one adjoining the trestle on thenorth side. The inside mattresses were lowered fromthe floor of the trestle and sunk by piling rock upon. THE JET FILE-DRIVER USED IN CONSTRUCTING THE TRESTLE them. They were 20 feet wide, 64 feet (the length offour bents) long and 5 feet thick. Those on the out-side were 20 feet by 20 feet in area and 3 feet in thick-ness. They were all built of brush and poles, with fiveor seven stops alternating in direction on the layers ofbrush and securely fastened by wire or rope to thepoles. The placing of the outside line of mattressesin position necessitated the construction of speciallaunching cars. These consisted of flat cars on whichframes or platforms measuring 20 by 24 feet were car-ried upon rollers. The mattresses were brought to thesite on these cars and, by means of a tripping gear and
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectwire, bookyear1898
