regarding extra storage. Adding a fy under the station is asking for trouble because 1. Access. You will need at least 6", preferably a lot more, to enable you to attend to trains. This leads to, 2. Gradients. To obtain the seperation required, you will need a long line of hidden track to achieve the gradient required. Models, particularly recent RTR dont like gradients. Realistically you would be looking at a hidden feeder line going all the way around the room, assuming youd be storing trains of more than 3 or 4 coaches it leads again to 3. Access. All that hidden track will come to be a pain in the ass for maintainance, cleaning, derailments, etc.