Electric locomotives first appeared in the 1800s. Several entrepreneurs experimented with small motors or batteries on short tracks but limited power and battery capacity slowed expansion into mainline rail service.
The growth of metropolitan areas and the use of tunnels spurred the development of the electric locomotive concept. Steam engines produced high volumes of smoke, ash and cinders that became unacceptable to the cities. As tunnel use increased in the cities and in mountain areas, the noxious fumes created health problems for the crews. Electric power produced no such pollution and, when cities began to ban steam locomotives from the city limits, electric development accelerated.
Electricity was not only recognized for its cleanliness, but also for its high power output. Electric locomotives became popular in mountain areas, in service areas requiring frequent stops and starts and for short runs with a constant high freight volume.
A major disadvantage of electric locomotion, and the reason it did not see a great expansion into mainline US railroads, is the infrastructure cost. Electrifying lines is extremely expensive and the railway companies could not justify it across the great expanse of US tracks.
The Virginia museum of Transportation has exhibits from two of the most successful electric locomotive services. The Virginian Railway EL-C #135 pulled coal trains through the mountains of Virginia and West Virginia. The Pennsylvania Railway GG-1 #4919 pulled passenger trains in the highly populated Northeast US for almost 40 years.