When the rails are in place the boards may be cut with a pad-saw to curves corresponding with the breadth of the track on the straight. If the boards incline to warp, screw some pieces of 1/8-inch strip iron to the under side across the grain, sinking the iron in flush with the wood.
The brass strip for the rails costs about one penny per foot run. Iron strip is much cheaper, but if it rusts, as it is very likely to do, the contact places will need constant brightening.
Points.—Fig. 45 shows the manner of laying out a set of points, and connecting up the rails. The outside wheel rails, it will be seen, are continuous, and switching is effected by altering the position of the moving tongues, pivoted at PP, by means of the rod R, which passes through a hole in the continuous rail to a lever or motor of the same reversible type as is used for the locomotive. If a motor is employed, R should be joined to a crank pin on the large driven cog—corresponding to that affixed to the driving wheel (Fig. 47)—by a short rod. The pin is situated at such a distance from the axle of the cog wheel that a quarter of a revolution suffices to move the points over. The points motor must, of course, have its separate connections with the “central station.” To show how the points lie, the rod R also operates a semaphore with a double arm (Fig. 46), one end of which is depressed—indicating that the track on that side is open—when the other is horizontal, indicating “blocked.” The arms point across the track.
[Illustration: FIG. 45.—Points for electric railway.]
Details.—The tongues must be bevelled off to a point on the sides respectively nearest to the continuous rails. The parts AA are bent out at the ends to make guides, which, in combination with the safety rails, will prevent the wheels jumping the track. Care should be taken to insulate centre rail connecting wires where they pass through or under the wheel rails.
It is advisable to lay out a set of points, together with motor and signals, on a separate board.
[Illustration: Fig. 46.—Double-armed signal, operated by points.]
Preservation of Track.—All the wooden parts of an outdoor track should be well creosoted before use.
The Electric Locomotive.
An elevation and a plan of this are given in Fig. 47. The two pairs of wheels are set close together, so that they may pass easily round curves.