Unlike New York, Philadelphia, Washington, and newer cities to the west, Boston had not been laid out on a grid. Many of its streets had begun as paths that wound around hills and swamps. As Boston matured into a major metropolis in the nineteenth century, it faced the challenge of moving people and goods around a crowded peninsula. At mid-century, the city introduced horse-drawn streetcars; by the 1880s horsepower had been replaced by overhead electric lines. But neither innovation solved the real problem: Boston's streets were simply clogged with vehicles. Disgruntled residents complained that it would be faster to walk across the stalled streetcars than it would be to wait for the cars to reach their destination.

There seemed to be only one possible solution: get the trolleys off the streets. Numerous proposals were floated for different types of elevated railway technology, most of it untried and unproven. One idea for a monorail received such serious consideration in the 1880s that the inventor built a full-sized demonstration line near Lechmere Square. But a shortage of funds kept this and other schemes from getting off the ground.

In 1892 a special commission charged with studying the problem recommended that trolley routes be run above and below Boston's crowded streets. In 1894 the Massachusetts legislature approved the plan and authorized a subway tunnel to move traffic below the most congested part of Tremont St. and an elevated railway to run overhead through the rest of the city. A group of Boston businessmen, including Eben Jordan of Jordan Marsh, established the Boston Elevated Railway Company.

The groundbreaking ceremony was held on January 20, 1899. Over the next two-and-a-half years, the company constructed seven miles of elevated track, ten elevated stations, two large multilevel terminals, and a huge power-generating station and designed and acquired 150 cars to run on the new elevated tracks. The Main Line El ran from Dudley Square to Sullivan Square, right through the heart of the city.

June 10, 1901 was a day of great civic pride. Early in the morning eager riders gathered outside both the Sullivan Square and Dudley Square Terminals. At 5:00 am, the gates swung open; the crowds surged up the stairs and rushed onto the platforms. When the departure gongs sounded at 5:30 am, the jam-packed trains pulled out, inaugurating 86 years of elevated train service in Boston.

Bostonians soon became accustomed to the rumble of the El and the screech of brakes as trains rounded curves or entered stations. The huge steel structures, painted olive green, became part of the fabric of the city. The cars were painted red with silver gilt striping and slate gray roofs. The interiors were equally handsome with varnished African mahogany woodwork, sky-blue ceilings, bronze hardware, and seats upholstered in red and black. The stations were sheathed in burnished copper.

Ridership rose steadily throughout the first decades of the twentieth century. Gasoline and tire rationing during World War II increased use even more. By 1943 325,000 people a day squeezed aboard the Main Line El trains. By then, the Boston Elevated Railway provided service on 52 different streetcar lines. In 1947 the Metropolitan Transit Authority (MTA) took over operation of the El.

By the late 1940s, the system was overcrowded, and the elevated railway fell out of favor. The public wanted subways. The original Green Line — the nation's oldest subway —had opened just a few years after the first El. As the city's subway system grew, Bostonians came to prefer underground to overhead transport. People grumbled that the huge overhead structures were a noisy, ugly eyesore, darkening and dividing the city.

In the 1960s city officials decided the Els should go. Beginning in the mid-1960s, the Orange Line El (the elevated railway that ran above the Washington Street corridor) was torn down and replaced by a subway line a quarter mile away.

The last section of elevated railway infrastructure was scheduled for demolition in June of 2004. On June 25^th, the last Green Line train rumbled down the elevated tracks around what was then the Fleet Center. The MBTA acknowledged that "the elevated portion of the Green Line has served us well for close to 100 years," but like most Bostonians, transit officials believed the removal of the old El tracks helped beautify the city. At least a few residents, however, felt the loss of another part of Boston's historic character.