Disclosed is an apparatus for transporting a substrate media sheet along a process path through a marking zone. The apparatus includes a marking zone, an air bearing support rail and a media cart. The marking zone marks the substrate media sheet. The air bearing support rail extends from a first location upstream of the marking zone to a second location downstream of the marking zone. The media cart conveys the sheet along the process path. The media cart includes a platen for holding the sheet thereon as the media cart translates through the marking zone. The media cart is supported along the process path between the first and second locations by the air bearing support rail. The air bearing support rail includes a gaseous layer providing a non-contact bearing support between an outer surface of the air bearing support rail and a non-contact support surface of the media cart.