Uh, electric train cars are all but self propelled, and could carry their own electricity if so desired. Trollies and street cars are individually powered. Sl

Uh, electric train cars are all but self propelled, and could carry their own electricity if so desired. Trollies and street cars are individually powered. Slip cars only made sense during the age of steam power, when locomotive power was supplied by huge coal powered engines with furnaces, before internal combustion and deisel made smaller power plants possible. It's interesting, but now we have monorails, magnetic levetation, induction and more, and the concept of coasting to a halt at a precise point pretty much only has utility in amusement parks.