which opened on November 14, 1885, and on one in Montgomery, Alabama, in April 1886. However, within a few months, Van Depoele switched to the trolley-pole system for the Montgomery operation. Van Depoele and fellow inventor Frank J. Sprague were "working on similar ideas at about the same time", and Sprague employed trolley-pole current collection on an electric streetcar system he installed in Richmond, Virginia, in 1888, also improving the trolley pole wheel and pole designs. Known as the Richmond Union Passenger Railway, this system was the first large-scale trolley line in the world, opening to great fanfare on February 12, 1888. The grooved trolley wheel was used on many large city systems through the 1940s and 1950s; it was generally used on systems with "old" style round cross sectional overhead wire. The trolley wheel was problematic at best; the circumferential contact of the grooved wheel bearing on the underside of the overhead wire provided minimal electrical contact and tended to arc excessively, increasing overhead wire wear. The newer sliding carbon trolley shoe was generally used with a newer grooved overhead trolley wire of a roughly "figure 8" cross section. The sliding trolley shoe provided better electrical contact (with a reduction in arcing), and it dramatically reduced overhead wire wear. Many systems began converting to the sliding trolley shoe in the 1920s; Milwaukee, Wisconsin converted its large system in the late 1920s. Curiously, Philadelphia did not convert its trolley wheels on its remaining streetcars until 1978. Although a streetcar with a trolley wheel may evoke an antique look, the trolley shoe is modern and more practical as well as economical. Description of the device A trolley pole is not attached to the overhead wire. The pole sits atop a sprung base on the roof of the vehicle, with springs providing the pressure to keep the trolley wheel or shoe in contact with the wire. If the pole is made of wood, a cable brings the electric current down to the vehicle. A metal pole may use such a cable, or may itself be electrically "live", requiring the base to be insulated from the vehicle body. On systems with double-ended tram cars capable of running in both directions, the trolley pole must always be pulled behind the car and not pushed, or "dewiring" is very likely, which can cause damage to the overhead wires. At terminus points, the conductor must turn