TABLE OF CURVES-(Continued.) Rad. Rad.[ Rad. Rad. Rad. Rad. Rad. Rad. Rad. Rad Rad., Rad. Rad. Rad. Rad. 1 5730 Rad. 10 10 10 10 20 20 30 30 30 30 40410 430 50 50 50 1910 1763 1637.1 1528 1432.5|1348.23 1273,3 1146 [1041.8996.52 4584 3820 13274.281 2865 |2292 |1000| 2425 2860 475 1975 1075 1625 1005 1318.35 to 1326.35 1350 700 4575 2700 3150 2050 1776.75 1826.50 4975 1700 1843.50 700 1850.50 2350 SIR, Office of the Western Rail Road Company, Boston, January 1st, 1838. COMPANY. The Board of Directors having "ordered that the Engineers be instructed to furnish plans of the various styles of Superstructure, with estimates cf the expense thereof" we have the honor, accordingly, to submit the following Report. - The superstructure, or rail-way, constructed as it may be in either mode we shall describe, may be considered as a frame work placed upon the road bed; the stability, and durability of which, will, of course, depend on its foundations, and the nature of the materials composing the railway. The foundations we shall suppose to be, as they would be, alike in either case their principal object being the equable support of the frame-work, and its protection from the influence of frost-to guard against the effect of which, in our latitude, it would be necessary, wherever the natural soil was the least argillaceous, or such as would retain and collect moisture, to excavate the road bed to the depth of say 2 feet (below which the frost would very seldom penetrate) and to consolidate thereon, in lieu of the mate rial excavated, sand, or pure gravel-or in lieu of either to construct masonry for the support of the sleepers or cross ties. Experience has shown that the better plan is to depend on sand, or gravel, rather than broken stone, or rubble masonry. It is much cheaper, generally, and in all cases equally efficient. The foundations being alike, however the rail-way may be constructed, their cost will not enter into a comparative estimate. The actual cost of preparing them would of course depend on the character of the ground traversed by the Rail-Road-for instance, in excavations through rock, or soil other than clay, the sleepers would be laid immedi ately on the road bed; or in other words, where sufficient protection was already afforded against the effects of frost, from the favorable character of the road bed, we should not of course, resort to artificial foundations. We shall suppose, however, in order not to be disappointed in the actual cost, that throughout the whole distance, artificial foundations shall be necessary. The cost then for excavating say 8 feet wide, and 3 feet deep; for procuring and depositing the suitable material, may, we think, then be safely assumed at $2346.66 per mile, per single track, and to this, if we add the cost of longitudinal sills of pine, hemlock, or such other timber, as may be most conveniently procured, the object and utility of which would be equably to sustain the rail-way, especially on embankments, and to facilitate the re-adjustment of the rails, when they shall have been deranged from the settling of the road bed or other causes; we must add for this item, say, $646.80 per mile and the total cost of the foundations would be $2993.46 per mile. We have said that the rail-way, or superstructure, may be regarded as a frame work, composed of the rails proper, tied together, at intervals, by the sleepers, or cross-ties, and as variously practised, the weight, form, and consequent strength of these Rails, determine the intervals at which they are tied, or supported. For instance the common flat bar, or rail, of ordinary dimensions, requires a continuous support, and is laid upon string pieces of wood or stone, and these stringers are tied together (in order that they may not spread or lose their parallelism) at intervals, dependant on the dimensions and strength of the stone or wood of which they are composed. This, however, is so poor a substitute for the several descriptions of rail way, which you are accustomed to see in this section of the country, and as we think, by unanimous consent, so unsuitable to your purposes, that we hardly think it necessary to dwell longer on it, than merely to state, that inferior as it is, the only saving in first cost (ultimately it is more expensive) would be in the diminished cost of the rail itself, and which would probably amount to about $2500 per mile-that is supposing the rail to consist of the flat bar, and the wooden string piece. The defects of this mode of construction are obvious. |