What were the first reliable streetcars powered by?
The horse drawn streetcar first appeared in America at about 1826 in New York City, on Broadway. In 1835 New Orleans became the 2nd city to used the horse drawn street car.
The next step was the cable car. San Francisco was a natural for such cars with its steeply inclined streets. That was in 1873. There were many other American cities to have an extensive cable car system was Washington D.C. was a bit different. That was because with the appearance of the electric streetcar, local politicians thought the necessary overhead wires and attendant poles were unsightly. Washington never had an electric streetcar system and its cable car system died after WW2.