The height of ambition of many boys is not only to own a miniature railway system but to build one. For some unknown reason, none of the boys’ papers or books have heretofore given any information on this interesting subject. The car shown in Figure 263 is such that it can be easily built by any boy willing to exercise the necessary care and patience in its construction. The first operation is to cut out the floor of the car. This is a rectangular piece of hard wood, eight inches long, three and one-quarter inches wide and one-half of an inch thick. Its exact shape and dimensions are shown in Figure 264. The rectangular hole cut in the floor permits the belt which drives the wheels to pass down from the counter-shaft to the axle. [Illustration: Fig. 263.—Complete Electric Railway operated by Dry Cells. Note how the Wires from the Battery are connected to the Rails by means of the Wooden Conductors illustrated in Figure 277.] The two pieces forming the wheel-bearings are cut out of sheet-brass according to the shape and dimensions shown in Figure 265. The brass should be one-sixteenth of an inch thick. The two projecting pieces at the top are bent over at right angles so that they can be mounted on the under side of the car floor by small screws passing through the holes. The holes which form the bearings for the ends of the axles upon which the wheels are mounted should be three inches apart. The bearings cannot be placed in position on the under side of the car floor until the wheels and axles are ready, but when this work is done, care should be taken to see that they line up and come exactly opposite to each other. [Illustration: Fig. 264.—Details of the Floor of the Car.] The wheels themselves cannot be made by the young experimenter unless he has a lathe. They are flanged wheels, one and one-eighth inches in diameter, and are turned from cast iron or brass. Such wheels can be purchased ready made, or it may be possible to obtain from some broken toy a set which will prove suitable. [Illustration: Fig. 265.—Details of the Bearing which supports the Wheel and Axle.] Each shaft is composed of two pieces of "Bessemer" rod held together by a short piece of fiber rod having a hole in each end into which one end of each piece of iron rod is driven. The wheels fit tightly on the other end of each of these pieces. They should be spaced so as to run on rails two inches apart. [Illustration: Fig. 266.—The Wheels and Axle.] The purpose of the fiber rod is to insulate the halves of the axle from each other. The electric current which operates the car is carried by the two rails which form the track, and if the axles were made in one piece or the halves joined together so as to form an electrical connection, the battery furnishing the current would be short-circuited, because the current would pass along the two rails and across the axles instead of through the motor. One pair of wheels are fitted with a grooved pulley one inch in diameter.