The long strips, bent at right angles to each other and marked A, A, B, B, in the illustration, are forced into the saw-cuts in the base over the strips marked D.
The small pieces, C, C, C, C, are placed in between the long strips, leaving a space between so that the flanges of the car wheels can pass. The pieces, C, C, C, C, should form a square open at the corners. The two long strips, A, A, should be at opposite corners diagonally across the square. B and B should occupy the same relative position at the other corners. A and A are connected together and B and B are connected together by wires passing on the under side of the base.
The ends of the track forming the figure-eight are forced into the saw-cuts at the edges of the base so that they form a good electrical connection with the small strips marked D.
It is quite necessary to use care in arranging a figure-eight track, or there will be danger of short-circuiting the batteries. The outside rails of the figure-eight, distinguished by the letter B in the illustration, should be connected together by the cross-over. The inside rails, marked A, should also be connected together by the cross-over.
In order to make a good mechanical and electrical connection between the ends of the rails when two or more sections of track are used in laying out the system, it is necessary to either solder the rails together or else use a connector such as that shown in Figure 277.
This consists of a small block of wood having a saw-cut across its upper face and a piece of thin sheet-brass set into the cut. The two rails are placed with their ends abutting and one of these connectors slipped up from beneath and forced on the rails. The piece of thin brass set into the wooden block serves to make an electrical connection between the two rails and also to hold them firmly in position. A small screw and a washer placed outside the track and passing through the brass strip will allow a battery wire to be conveniently attached.
Fig. 277.—A Connector for joining the Ends of the Rails.
The steel rails should be occasionally wiped with machine oil or vaseline to prevent rusting, and also to allow the car to run more freely wherever the flanges of the wheels rub against the rails in passing around a curve.
Four dry cells or three cells of storage battery should be sufficient to operate the car properly. If it is desirable, a small rheostat may be included in the battery circuit, so that the speed of the car can be varied at will. The motor and the wheels should be carefully oiled so that they will run without friction. The belts should not be so tight that they cause friction or so loose that they allow the motor to slip, but should be so adjusted that the motor runs freely and transmits its power to the wheels.