verse section of the Saratoga railway, constructed in the latter way, a railway of this kind being considered well adapted for swampy districts, and where forests abound. The bed of the railway is first formed with parallel trenches, 18 inches square, filled with small stones, which serve as a drain to keep the timbers dry, and cross trenches are made in a similar manner, and to attain the same object, under the cross sleepers. Upon the parallel trenches, along the line of the railway, are first placed longitudinal timbers of yellow pine, with a scantling of 5 or 6 inches by 8 inches, and to these, at three feet apart, are firmly secured transverse wooden sleepers of white oak, (cedar, or locust, or other wood,) sometimes 6 inches square, and at other times with a scantling of 8 or 10 inches broad, and 10 inches deep; and, lastly, the longitudinal wooden runner, 6 or 8 inches square, which forms the line of rails, is fixed; upon which the plates of iron of the size previously stated are laid and fastened with iron spikes with the heads made flush with the plate. On other lines, as the New York and Boston, the under timbers are dispensed with, and transverse sleepers, 7 feet long and 8 inches square, are laid, upon which the longitudinal timbers are fixed, surmounted with the plate rail. On the Philadelphia and Columbia railway, 82 miles in length, under the management of the state, several plans have been tried experimentally. On the Baltimore and Ohio railway, several miles of rails are laid with granite sills, or a continuous curb, in pieces from 5 to 9 feet long, 15 inches broad, and 8 inches thick, upon the inner edge of which the iron plate is spiked down to tree-nails of oak: on other lines the blocks are one foot square, and rest on a stratum of broken stones. A short distance of the Quincy railway is likewise laid with stone blocks. Some of the rails, from the sharpness of the curves, are connected together with iron ties. It has been found necessary, to prevent impairing the efficiency of this kind of railway, to place the iron rails more towards the centre of the blocks. WOOD RAILS. In this country the system of wooden railways has lately been revived by Mr. Prosser, chiefly to take advantage of his guide wheel, and a few miles of timber rails have recently been experimentally laid down at Wimbledon Common. The rails (fig. 9. a, a,) are formed of square blocks of wood, beech or hard wood, without any protecting iron plate, 9 feet long, and 6 inches square, attached to wooden sleepers b, and secured by wooden wedges, forming one great frame of longitudinal and cross sleepers. A part of the timber has been subjected to Mr. Payne's, and a part to Sir Thomas Burnett's patented process for increasing the durability of timber. Mr. Prosser states that the advantages to be derived from the use of his patent guide wheels in connection with the wooden rails are, that, from the greater bite wheels have on wood than on iron, a steeper class of gradients can be ascended, that shorter curves can be taken with safety, and that the general liability of carriages to run off the line is di minished, to which he adds, the cheapness of the original construction. Mr. Prosser has done away with the flanches on the carriage wheels, but considers that the advantages derived will be greater from the substitution of a guide wheel for the flanch on the bearing wheels, and that the invention is equally applicable to iron rails as to those of any other material. PATENT CAST-IRON EDGE RAILS. Although many plans were devised after the introduction of the edge rail into this country, no very decided improvement took place till the year 1816, when Mr. Losh, of Wallsend, and Mr. George Stephenson, who was at that time at Killingworth, obtained a patent for a cast-iron rail, which was at the time deemed an improvement over the common mode. The practical evil then existing in the system of laying the rails was the obstruction which the waggon wheels met with at the joints, and from the shock that was given, the rails were displaced and broken. This led to different plans of rails and chairs being proposed as a remedy. The object of the patent was to fix the rails immoveable in the chairs. The rails were joined by what is termed a half-lap joint, with a pin or bolt which fixed them. The object intended to be effected was, that the end of one rail should not rise above that of the adjoining one, and securing the rails from yielding in the event of the block sinking. Fig. 10. shows the joint and block of the patent rail. Fig. 10. Fig. 11. Fig. 12. A somewhat similar form of a rail was Fig. 13. proposed by Mr. B. Thompson, and tried at the Brunton and Shields railway. In this plan the chair had only one cheek or side, and the rail was fastened to the chair by means of a screw-bolt. Fig. 13. is a transverse section of the rail chair and screwbolt. This plan of fixing with screws was found to be attended with inconvenience in practice, wedges or keys being preferred. |