Storing a typical 1/8th scale freight car takes from 7 to 8 square feet of storage
space in your shop or car barn. And that assumes you are NOT storing them on stands.
If you have lots of indoor storage space you are all set. But if you are like many
of us - garage, shop, and shed space has some real limits.
One solution is to try to make better use of the space you do have. And here's a solution I've been using for almost 18 years. Store the cars vertically.
A car standing on end typically requires less than two square feet of floor space. In a perfect world a typical 10 by 16 "barn" style shed could store 80 cars in this mode. In reality, you need a place to walk and move cars around, so don't bet on the 80 number.
Example of boxcars stored vertically
Too bad this doesn't work well with locomotives.
Another goal is to minimize or prevent cosmetic damage to the cars during storage, loading, or unloading. The dollies are designed to protect the paint and details. One requirement is to insure that the "B" (brakewheel) end of each car is always up. There are less details to deal with on the "A" end.
Also, each type of car requires a dolly adapted to only that car or car type. Notice that some require the use of straps either during storage or to hold the dolly on when changing modes. Hopper cars only need a "C" clamp to hold the dolly on.
Special Dolly for Gondolas
Underside of a Gondola Dolly
(You also get access to the bottom of the car)