Railroad electrification in the United States began at the turn of the 20th century and comprised many different systems in many different geographical areas, few of which were connected. Despite this situation, these systems shared a small number of common reasons for electrification.[1]
Most of the systems discussed in this article are either no longer electrified, or are now part of the Northeast Corridor and Keystone Corridor systems used by Amtrak and several commuter rail lines. A few isolated systems operate exclusively for hauling coal from mines to power plants. Most mass transit, streetcar, and interurban systems were electrified very early (many from the beginning) but are not within the scope of this article.
The Association of American Railroads opposes electrification due to its high capital costs.[2] The Environmental Protection Agency states that the entire United States railroad network only contributes to 0.56% of the nation's greenhouse gas emissions,[3] and so electrification of the network would give negligible benefit to the environment.[4]