Most streetcar and interurban lines operated only double-end equipment that did not require loops at the end of the line. Interurbans included the three Insull lines, except of course for the North Shore’s observation cars, Pacific Electric, notable for double-end mu PCCs, Dallas, with its double-end PCCs, Scranton, Wilksbarre, Altoona, Third Avenue Transit in New York, New Bedford. Providence, Connecticut Company, Ottawa, Red Arrow and Philadelphia and Western, Providence, Portland, OR, Baltimore and Annapolis, West Penn, Yakima, Chico and Marysville-Uba City on SN, Key System, Atlanta, Omaha and Council Bluffs, Des Moines, Marion, Fort Collins, naming those that come to mind that operated after WWII.
Illinois Terminal is a special case, with some single-end interurban cars, but all local St. Louis-area suburban equipment double-end, including its eight PCCs. Lehigh Valley Transit had only double-end local cars but many single-end interurban cars. Ditto Waterloo, Ceder Falls, and Northern.
Then there are those that used exclusively double-end equipment until buying PCCs. Los Angeles Railways, Johnstown, Boston, San Diego, San Francisco, Cincinnati(?).or in the case of Atlantic City, Brilliners.
And there are those that had a mixture of double-end and single-end equipment and then used single-end PCCs. Montreal, Vancouver, Philadelphia, Brooklyn, Baltimore, Washington, Birmingham, Pittsburgh, with the single-end non-PCC car usually the most recent before the PCCs.
And those that never used PCCs, but the more modern cars were single-end. Indianapolis, Richm