Notes on Track Volume 1; Construction and Maintenance (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1904 Excerpt: ...switches for all, or nearly all, spur tracks, trailing switches; whereas, in making a round trip with a train over a single-track road or division, every switch on the line becomes a facing switch to that train once during the trip. Also, on double track the total number of switches is divided between two tracks, so that a train in going over the road in one direction does not pass over all the switches and frogs on main track, as it necessarily must on single track. 110. Comparative Cost of Construction and Maintenance.--The first cost for rails, ties, fastenings and ballast for double track is twice that for single track, but the same ratio does not hold true in other particulars--it favors always the double track. Thus, for instance, in earthwork with slopes 1$ to 1, a roadway 18 ft. wide, in cuts or fills of 10 ft. depth, may be widened out to 31 ft. (the corresponding width of roadbed for double tracks at 13 ft. centers) by the handling of only about 40 per cent more material, the proportion of additional material growing less as the depth-of cut or fill increases. The same ratio will hold true for the increased cost of masonry for bridge abutments for double-track, as compared with single-track, structures. In most regions cuts and fills of the above dimensions are only ordinary with roads handling a traffic so large that they can afford to double their tracks. And besides, the cost for filling or excavating per yard of material for an additional track should be less than that for a single track, after the single track is once in operation, owing to the increased facilities for hauling, handling by machinery, etc. Taken all around, therefore, the cost for earthwork for a second track should usually not exceed 50 per cent of that for a single track on ...