. The ways of our railways . Adoctor is kept on the works to attend immediatelyto all cases of sickness arising from this cause, theremedy being to put the patient back in an air-lock specially kept for this purpose. The fact thatinstant relief is thereupon experienced supports thetheory that small globules of compressed air havemade their way between the layers of the skin andexpanded when the workmen returned to ordinaryatmospheric pressure. Compressed air has often to be resorted to in theconstruction of railway bridges over water, the best-known example being the sinking of the caissons,or
. The ways of our railways . Adoctor is kept on the works to attend immediatelyto all cases of sickness arising from this cause, theremedy being to put the patient back in an air-lock specially kept for this purpose. The fact thatinstant relief is thereupon experienced supports thetheory that small globules of compressed air havemade their way between the layers of the skin andexpanded when the workmen returned to ordinaryatmospheric pressure. Compressed air has often to be resorted to in theconstruction of railway bridges over water, the best-known example being the sinking of the caissons,or cylinders, which formed the foundations of thegreat Forth Bridge. This mighty structure is suffi-ciently high to clear all navigation, but often incrossing a navigable river a railway bridge is con-structed with a swing span, which is usually workedby hydraulic machinery and interlocked with thesignals at either end of the bridge. The building of bridges over or under publicthoroughfares is often a matter of some bother to. LAYING DOWN OF THE LINES. 77 the agent, especially where traffic on the road mustnot be interrupted, even for one hour. It is usualto divert the road whenever possible, or else to builda temporary bridge alongside the site of the per-manent one. In places where the foundations arebad owing to the presence of water in the ground,serious delay may occur to the works, owing to thenecessity for bringing more men to the spot fromanother job, or the compulsory taking up of thetemporary road to allow of additional foundationsbeing put in. Though the erection of a bridge looksa very simple matter to the passer-by, probably hewould be surprised if he were aware of the manydetails attendant upon its construction. The orderin which it is to be built has to be carefully planned,so that the masons and bricklayers may not be over-whelmed with work at one time, and standing idlea few weeks afterwards. Where a viaduct has to be built (provided thatthe ground is not waterlo
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroa, bookyear1910
