William O. Douglas,
United States v. Seaboard Air Line Railroad Company…
“ It may properly be said there is no 'train' in a true 'switching' operation. But when cars-at least in substantial number-are being received from consignors or delivered to consignees in an assembled unit of engine and cars that moves a substantial distance, the operation is intrinsically no different, for purposes of the Act, than a main-line haul. ”
