Franklin Roosevelt actually said...

"the exercise, as hereinafter specified, of the powers vested in me is necessary to insure, in the interest of the war effort, the operation of the said systems"

"Possession, control, and operation of any transportation system... shall be terminated by the Director when he determines that such possession, control, and operation are no longer necessary for the s..."

"the Director shall observe the terms and conditions of the directive order of the National War Labor Board"

"In time of war, the President is empowered, through the Secretary of War, to take possession and assume control of any system or systems of transportation, or any part thereof"