On Sept. 1, 1897, Boston, Massachusetts began running the first subway system in the United States. The public transportation system, which took approximately two years to construct at a $5 million cost, is known today as the "T." While Boston may have constructed the first American subway, New York City is home to the country's largest system. With its first lines completed in 1904, New York City now has 26 train lines, the longest being the 8th Avenue train which runs approximately 32 miles.
In the early 20th century, Cincinnati, Ohio created an ambitious and complex plan to construct its own subway system. However, after many financial problems, and more than 20 years of on-again, off-again constructing, the incomplete project came to a halt in 1948. Today, while a single train has yet to run through the tunnels, several major sections of the underground system still exist.
As of 2010, there are more than 50 subway and transit systems spread throughout the United States. These complex and well-managed systems continually undergo change and improvement. In October 2010, the city of Philadelphia announced a plan to introduce a pilot program for one of its train lines that would help recycle and store energy created by the train. The power could be saved and used by the trains, or possibly transferred to the power grid.
