Disclosed is a moveable platen cart for handling sheets of substrate media in a printing system. The platen cart includes a cart frame, a media platen, a vacuum port and a valve. The cart frame is configured to translate along a process track. The media platen is secured to the cart frame. The media platen has a foraminous upper surface for receiving a substrate media sheet thereon. The media platen has a subsurface cavity in fluid communication with the foraminous upper surface. The vacuum port is for evacuating air from the cavity. The valve is for selectively closing and opening the vacuum port.