Model Railroader had an article about a folding layout afew years back that was really neet. If memory serves me right it was N scale but the same principals could apply to HO scale as well. When laying the track where the layout would fold you would want to have a removable piece of track so the folding process does not cause any damage. Even if you were to just gap the rails the process of folding the layout would cause the ends of the gap to hit and cause damage. Making a larger gap would cause derailments.
Have you thought about a modular layout? I built a 5x9 layout that used 4 pieces that were 2.5x4.5 and 2 of each piece bolted to a piece of ply that kept them linked together for storage and moving. Since the scenery was put to the center when they were bolted together nothing got damaged in transit. Here are a couple of pics.
One module's framework
2 modules bolted together to form a 2.5 x 9' section.
Sorry I dont have pics of what it looked like when set up for storage. I used complimenting pieces to give the scenery the best protection and made sure all of my buildings were removable.
A Veteran, whether active duty, retired, national guard, or reserve, is someone who, at one point in his or her life, wrote a blank check made payable to "The United States of America" for an amount of "up to and including my life."
Owner of the South Massey Railway.