. The elements of railroad engineering . tepoint is shown in Fig. 372. Line of Sight Fig 3T2. The line A /> C from the P. T. at A to the P. C. at C isstraight, but the transit pole at C can not be seen throughthe transit aty^ on account of the change of grade at B. Itis, therefore, necessary to establish an intermediate point atB on the line ABC. The transit being set up at B, bothP. T. and P. C. are in full view. A good example of referencing is shown in Fig. 373. Thereference points consist of plugs driven flush with theground and protected by substantial guard stakes, which are RAILROAD
. The elements of railroad engineering . tepoint is shown in Fig. 372. Line of Sight Fig 3T2. The line A /> C from the P. T. at A to the P. C. at C isstraight, but the transit pole at C can not be seen throughthe transit aty^ on account of the change of grade at B. Itis, therefore, necessary to establish an intermediate point atB on the line ABC. The transit being set up at B, bothP. T. and P. C. are in full view. A good example of referencing is shown in Fig. 373. Thereference points consist of plugs driven flush with theground and protected by substantial guard stakes, which are RAILROAD LOCATION. 845 marked with the letters R. P. Where the located line trav-erses timber or brushwood, the ordinary stakes on thecenter line should be replaced by much larger ones. Theyare best cut from saplings about 3 feet in length and from2^ to 3i inches in diameter. A place for the stake is madewith an iron bar, and the stake driven at least one foot inthe ground with a sledge hammer. Special care is taken in ffiPZw^ and^I^^Guard Stake. JtJ^Plug and Guard Stake Plug andGuard Stake Fig. 373. guarding points of curve and tangent. While the right ofway is being cleared a man is detailed to look after thestakes and hubs on the center line, as many will be disturbedor torn out of the ground while hauling logs and timberfrom the right of way. When the clearing and burning iscompleted, the center line should be rerun, restoring alllost or disturbed stakes. Transit points, if well set, willrarely be disturbed. When the center line is restored thetransit points are referenced. A little care and judgmentwill enable the engineer to select reference points which willremain undisturbed during the work of the work is heavy these points will be further re-moved from the center line than at points where the workis light. When the grading is completed, the original points ofcurve and tangent can be restored and the center line runin from both ends of the curve. Any small err
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectrailroadengineering
