I have never thought of it in the way you are saying it. I suspect you do not know, what technically is called a train. Every train movement requires a crew. But in the case of remote control, they might not be in it, but only next to it and sometimes within a quarter mile of it. Back in the early 60's we had a train we regularly ran from Roseville California into Oakland, across the bay from San Francisco. It had a caboose in the midst of the train, but that cab did not mark the end of the train. The cab at the end of the train was lit with markers that indicated, "End of Train". There was one crew for all of it. In Oakland, all that was behind that middle caboose stayed in Oakland. The middle cab became the new EOT marker. A new crew then took that train around the bay and back to San Francisco.