@Wutter Mine have been on a Saturn 2, others have been on Saturn 2 and 3. As for orientation - I prefer to print vertical, A end down, and support the end sill, truck and weight alignment, stake pockets, and whatever else may have issues. Another gentleman has successfully printed them at a 45 degree angle. These cars are not designed quite the same way as my pressure vessel loads which are optimized for vertical printing. A few illustrative images from the last print, with a bonus of the 45 degree print and a different example of how to support:
As you can see in the background, the center sills are also done vertically, with the bottom end, crossbeams, and alignment pins being supported.
Edit to add: I am using whatever settings Elegoo had when they included Chitubox. I may have made a minor tweak at some point... haven't really messed with anything as the default settings work pretty well. Using their space gray 8k resin.
Edit no. 2: All my supports are hand placed on the cars, no auto supports. Same with the center sill. The brake system details and coupler box covers I'm far less particular about and just let auto supports reign there.