The first electric lines were introduced in 1898 by the B&O railroad to be used in the tunnel under Baltimore harbor. They were slowly introduced in other areas. The area that received the most electrification was around New York. The New York Central electrified its line into Manhattan allowing Park Avenue to be covered, the the Pennsylvania did the same when it opened a tunnel under the Hudson. Electric locomotives were clearly efficient; they could start faster with less power then steam locomotives. There was however, a high cost in the installation. The most ambitious project was the electrification of the main line of the Pennsylvania Railroad between New York and Washington.

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