I currently have eight long tracks for train storage in the shadow station. I have a bunch of trains in there, some of them are also pretty long, (472cm) which each use up most of a track. Other tracks have up to three shorter trains parked, waiting their turn to come out and run about.
The problem is that the layout is at its limit, a train can't run out unless it has somewhere to go, and if a friend wants to add a train of theirs, I find the system is choked, I have to find a place to park one of mine, so that there is room for theirs. I also have a bunch of locomotives that are in a display case, some still need decoders that need space on the layout. I also have some commuter trains such as the Primex Berlin S-Bahn train and a nice railbus that I would like to mix in with the more modern S-Bahn trains.
I also need a long track on which to perform maintenance on passenger trains that have been semi-permanently coupled. The maintenance track can also be used for adding and removing trains from the layout without holding up the mainline.
So, I decided I need some additional storage tracks for short trains. A scheme was hatched that would allow trains to depart the existing layout at two levels, each go through a fiddle yard of tracks and then go along the back wall of my basement to a common turning loop, and then return either to the original level, or the other level. The two levels of my existing layout have a height difference of 255mm, so the fiddle yards and the tracks going to the turning loop are going to be on an incline in order to traverse the height difference of the two levels.
Here is one of my concept track designs for the fiddle yards. The idea is to have two of these, one above the other, giving me about 20 new storage tracks!