Newark already had electric streetcars as early as 1880. They became so popular that there was a serious problem with streetcar congestion at this particular intersection of Broad and Market streets. In 1910, more than 552 streetcars per hour were passing through the intersection during peak times. By 1913, the number had increased to 600 per hour. In 1916, a new trolley terminal was built to divert some of the streetcar traffic from this intersection.
Although streetcar service continued to flourish along with motor buses and later subways, it met its demise as a result of the trolley bus. The trolley bus could follow the same streetcar routes, but was also more versatile because it could run on the overhead electric power or on diesel where there were no overhead lines. Whereas streetcars let their passengers off in the middle of the street, trolleybuses could pull over to the sidewalk. Trolley service on Broad street ended in 1937. Ten years later, there were no more streetcars at all in Newark.
This card shows two different streetcar types side by side. I am guessing that the larger one was an interurban.
This card was sent to Sadie Rogers in Buffalo in 1906 with the cryptic message on the front:
July 21/ 06
Rocks whereon greatest men have often wreck'd.
The quote is from Paradise Regained by John Milton.