UP unveiled on Thursday a new type of autorack car, called the Auto-Flex, that can support both bi-level and tri-level configuration in the same structure. More info here: http://rail-news.com/2010/09/02/union-pacific-railroad-unveils-prototype-autoflex™-convertible/
If you notice the side ladders to access the upper levels of the car are inside when the doors are closed.
