2. Rails changed the landscape of cities
Even before the Civil War larger American cities and even some medium size towns were equipped with streetcars, mostly privately owned, which followed their routes on rails, pulled by horses or mules. The horses of course left behind their waste on urban streets, and their presence, as well as those pulling private carriages and taxis, caused laws to be enacted in most cities banning the presence of noisy and frightening steam engines to pull the streetcars. Most streetcars moved at a sedate walking pace and were thus easy for pedestrians to espy and avoid. With electrification all of that changed. Streetcars and trolleys could then move at higher speeds, and the obvious problems interacting with pedestrians and horse-drawn vehicle quickly presented themselves.
The cities and towns equipped with streetcars began looking for alternatives other than intermingling horse drawn vehicles with streetcars. Larger cities began to elevate the tracks above the streets, with elevated station platforms connected to the streets with stairways. Boston began building the first underground urban rail network in the 1890s, New York followed about a decade later. The railways also expanded outwards from the cities to nearby towns, and dwelling outside of the main business district, able to commute to work by reliable and affordable transportation, became an option for more and more workers and families. Most unskilled hourly laborers continued to reside close enough to their place of employment to walk to work.