Trams, also called streetcars, were four-wheeled vehicles that traveled over rail systems called tramways, or street railways. Horse-drawn trams quickly replaced horse-drawn buses, or omnibuses, for a simple reason: steel wheels on steel rails gave a smoother ride with less friction. Horses could also pull twice as much weight on wheels rolling on steel rails as they could on dirt roads. The first street railway was built in New York City in 1832. The New York and Harlem Railroad route was originally a mile long and used two cars to transport thirty people each. Within two years the route had grown to four miles and ran cars every fifteen minutes. The popularity of the streetcars soon spread to Europe, first to Paris in 1853, then to England in 1860. Steam-powered trams were devised in Cincinnati, Ohio, and in London, England, but existing tracks built for horse-drawn vehicles...