I agree with the above with a couple of comments.
Is the yard setup with classification tracks as part of a switching layout, or is the yard more a staging yard? I personally think if you plan to do switching in the yard it needs to be flat, whether single or double ended, to prevent cars from coupling when you don't want them to.
If it is a staging yard where full trains are parked and will stay together, the engine would keep the train from rolling on a shallow grade like that. This is assuming you don't change your trains very often. If you regularly build trains or take them off the track in a staging yard, go with the above advise from BoilerMaker.
