Floating shelves can be an efficient means of storing rolling stock.
You don't need to be in the hobby long before you've accumulated a decent inventory of rolling stock. The question then becomes, how do you manage it? Ideally, you want a system that allows you to quickly see your roster and rotate a piece onto the layout.
Often clients will say they want a yard on the layout and then say they have no interest in switching operations. They want the yard for storage. The problem there is that yards take up a huge amount of room, often a third or more of your layout space. Do you want to dedicate that much of a footprint that could be used for elements that are of more interest to you? In addition, as yards fill up, it is hard to see the cars on the back tracks. You also need to keep the cars on the rails as you cycle cars in and out of service.
The other common storage method is in their original boxes in cabinets, often in another room. The problem with that is you can't see the cars at a glance. In addition, every time you need a car you need to find it on the shelf and then dig it out of the box.
On my layout, I use open-top, floating shelves adjacent to the layout. There are no rails on the shelf surfaces. This method allows me to quickly find the car I'm looking for, pluck it off the shelf, and place it on the layout. I split my roster into two groups. The cars I use the most go on the open-top shelves. Cars that I rarely use, stay in their boxes and are stored in a closet.
I picked the shelves up at the local hardware store. Note the trim strip around the edge to keep the cars from rolling off.
Here's a closer look at the shelves.
Like so many good ideas, this one was obvious...so obvious that I never thought of it! I'm going to enjoy this a lot more than I will carrying boxes of trains out to the garage where I intend to build my railroad. Thanks!