Streetcar and Trolley
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 could not support the weight of an engine. The next step in the development of self-propelled cars was the cable car. Cable cars could still be powered by a steam engine, but the engine did not have to be mounted on the vehicle. Instead, an arm suspended from the vehicle engaged a moving cable buried beneath the street. The cable was moved by a steam engine located somewhere along the route. Andrew S. Hallidies's 1873 San Francisco system was the first to use the cable car, and it grew to more than 500 miles of cable tramways by 1890. German engineer Ernst Werner von Siemens built the first electric-powered trams in Berlin in 1881. He used one rail to supply current and the other to return current. This method was soon found to be dangerous, and he quickly introduced an overhead contact wire. In 1886 a tram route with electric motors operated in Mobile, Alabama.
This early direct current system, based on Siemens's updated technology, received power through an overhead wire and completed its circuit through one of the rails in the street. The device that collected electricity from the overhead wire was known as a troller. Electric-powered trams, or streetcars, therefore became known as trolleys. Once Frank J. Sprague (1857-1934) perfected the swivel trolley pole, electric streetcar lines expanded to nearly 22,000 miles (35,398 km) in barely a dozen years. In fact, by World War I, most towns and cities had a trolley route of some kind. Though electric-powered trolleys operate safely and quietly, their range of movement is limited by the location of guideways. Trolleybuses, or trackless trolleys, allowed varied routes and steering flexibility and became popular during the 1920s and 1930s when much of the rails of the older systems began to deteriorate. Rather than laying new track, transit companies invested in the new rubber-tire vehicles. Unfortunately, they were also too limited in range when compared to newer gasoline-powered bus es, and in most places, they declined in popularity during the 1950s. In recent years, however, electric transit, in the form of trolleybuses, has made a dramatic return in cities plagued by heavy traffic and air pollution.
During the 1970s and 1980s, several surviving rail systems in the United States were rebuilt, modernized, and even extended, and by the late-1980s, eight new lines were built in Canada and the United States. No longer called trolleys or streetcars, these new systems are part of the modern "light rail" concept which has proven to be an excellent middle ground between bus operations and heavy rail rapid transit. These new light rail systems are characterized by simplicity and economy, as exemplified by the adoption of such systems as a self-service, barrier free fare collection system. The standard vehicle for these new urban electric railways is the articulated light rail vehicle. By the beginning of the 21st century, the old streetcar and trolley promises to be reborn in the light rail boom, as more than a dozen American cities have projects planned or proposed.
Beyond this near future, light rail technology may evolve into a fixed-guideway concept that has been under development for some time. Called System 21, this transit system consists of streamlined, pod-like cars that are cantilevered from either side of a single, elevated beam. These cars are built of a rugged fiberglass/plastic composite and have steel wheels that travel in a contoured rail truck that is recessed in the beam. They are powered by standard commercial DC power delivered by the beam. The cars of this fixed guideway system will appear to hang over the edge of the beam, but will be able to carry large numbers of passengers at speeds of up to 60 mph. Finally, unlike monorail systems that require expensive dual tracks or work only in a closed loop, this design offers simultaneous two-way traffic on a single, 6-ft wide steel beam.
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