. The Street railway journal . ade and the sub-grade isprepared for considerable distances, depending in lengthon local conditions, before any concrete work is done. Theties are then laid in the excavation and are blocked up totheir regular positions, after which the rails are attachedto them. The layer of concrete on which the ties rest andin which they are imbedded is then laid up to 2^2 ins. abovethe top of the ties, except at the joints, where it is stoppedlevel with the top of the ties in order to permit the railsto be welded later without disturbing the concrete. The concrete is produced
. The Street railway journal . ade and the sub-grade isprepared for considerable distances, depending in lengthon local conditions, before any concrete work is done. Theties are then laid in the excavation and are blocked up totheir regular positions, after which the rails are attachedto them. The layer of concrete on which the ties rest andin which they are imbedded is then laid up to 2^2 ins. abovethe top of the ties, except at the joints, where it is stoppedlevel with the top of the ties in order to permit the railsto be welded later without disturbing the concrete. The concrete is produced by a mixer outfit mounted ona frame carried by two four-wheel car trucks. This outfitwas built specially for use in this work by the Drake Stand-ard Machine Works, of Chicago, and is operated over therails as they are blocked up in place before the concrete islaid. The frame of the outfit is 48 ft. long and is built ofstructural steel. A standard Drake concrete mixer ismounted under one end of the frame where it can discharge. STANDARD GROOVED RAIL SECTION the concrete directly into place under and around the tiesand rails. Concrete materials are supplied to the mixer bya flight chain conveyor which runs the full length of theframe, the materials being shoveled into the conveyor fromstorage piles on the pavement on the roadway side of thetrack. The concrete is made in the proportions of 1 part cement,3 parts sand and 6 parts broken stone. These materialsare piled along the track in such manner that as they areshoveled into the conveyor they are in the proper propor-tions for the concrete. This is accomplished by first plac-ing a layer of sand of a predetermined depth and width onthe pavement, and over that a layer of broken stone andthen a layer of cement. The sand and stone are deliveredin wagons, from which they are dumped directly in placeon the pavement, the layer of sand being kept considerablyin advance of the stone. The required width and depthof the sand and stone is m
Size: 1354px × 1845px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
