For many decades now, the New York City subway/el complex has only 3 places where trains actually turn around: The 2 loops at South Ferry, and the old City Hall Loop. At ALL other terminal stops, they deal with all EMU trains being double ended and change ends, almost always in conjunction with a crossover or a series of crossovers to get the train on the right track. My question is: Prior to the middle of 1903 when all service was elevated and some or all of the service was powered by steam locomotives, how did they deal with changing directions? If they did it by running an engine around the rest of the train, that would explain why the archival photographs sometimes show the engine going boiler first and others show it runnning cab first.