OP RAIL-ROADS.

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view; and Fig. VIII. a section of the most improved formof this kind of rail;—c c c c are the rails, four feet long,placed upon stone supports, about a foot square, and eightinches deep, as shewn in Figs. VI. and VII.; at the endsof each rail, when they are laid against each other on thestone support, a small square piece is cut or left out incasting the metal, increasing in size upwards, so that, whenthe two ends are laid together, these two holes form a sortof square hole through the ends of the rail, narrowingdownwards; a perfectly level and horizontal groove is thenmade on the top of the stone, and the rail imbedded in it;a hole, corresponding with the square hole of the rails, isdrilled into the stone, about half the depth; an iron pin isthen driven into the stone through the hole in the rails, whichhaving a bevilled head fastens them down to the stone,one half of the pin securing one rail, and the other half theadjoining rail, as shewn in the drawing; these nails aregenerally from three to four feet long.

Fig. VIII. is a section of the rail; a d, the bottom orwheel-track, about four inches wide and an inch thick, whichis made quite level; d e, the flange or upright ledge to keepthe wheel upon the part a d of the rail, and a f a, the flangeprojecting downwards to strengthen the rail; the uprightflange is the same height throughout the whole length ofthe rail, as shewn in Fig. VII. being no higher than isnecessary to secure the wheel upon the proper track, andwhich of course requires no greater depth in one part thananother, and the height adding to the friction of the carriage-wheels, it will necessarily be made as low as possible; hencewe find it never exceeding three inches. This restriction inthe height of the upright edge limits the form of the section,and renders it not that of the greatest strength ; the resist-ance to fracture being as the breadth and square of the depth,the horizontal part a d of the rail, while it adds to the cost,