liable to be injured by high winds or the accumulation of ice and snow; and, furthermore, as the conductors are below the ground the danger of burning out motors and generators by lightning would be eliminated, and this is a serious matter with all trolley roads, especially in cities. Country roads do not suffer so much from lightning, because when there is a heavy thunderstorm the generators are stopped and the trolley poles are pulled away from the wire, the cars remaining stalled on the track until the storm passes over. This course can not be pursued by city roads, for the passengers feel that, lightning or no lightning, they must reach their destination, therefore the cars must continue to run and take their chances.
Lightning, however, does not strike trolley lines as often in cities as in the open country, owing to the fact that there are so many iron buildings and roofs to attract it in other directions.
Fig. 28 shows the appearance of the street surface when an underground system such as is illustrated in Fig. 27 is used. This figure is a photograph of the Capital Traction Company's lines in Washington. After looking at this picture one can not deny that the appearance of the streets of a city is greatly improved when the overhead wires are removed, but underground systems which require a plow to run in a groove are not without objection, for the groove forms a dangerous trap into which the narrow-tired wheels of light wagons can readily drop, and the toes and heels of horse-