O scale rolling stock storage

Like every model railroader, I have more rolling stock then I can fit on my layout. Since my layout is currently only 12 feet long that isn't saying much. I enjoy modifying and weathering freight cars (I spend 10x more time doing that then actually running them) so I purchase them at train shows and online during sales. But unlike my collection of HO scale equipment which I keep in pizza boxes lined with felt, and my N scale equipment which fits in shoe boxes nicely, I needed a better method of organizing my O scale stuff.

Most of my locomotives were purchased new in boxes, and I keep those boxes to protect the expensive engines. If I need to mail them out for repair it will make the process easier. But for freight cars, I usually just rip the ends off the boxes (the ends contain information like manufacturer numbers and road numbers) and then recycle the rest. 

I found that $10 plastic storage boxes from Target (66 Quart, interior dimensions 12.5"H x 13.5"W x 19.75"L) are perfect for the job. They are clear and easy to see into, stack well, aren't very heavy, and are priced right. See here.

To keep the train cars safe, I discovered that "Savoritz" cracker boxes from Aldis are just the right length for large 60' long freight cars. Every couple of months I go to the store and pick up an empty cracker box (and sometimes load it with groceries I am actually buying), and when I get home I use a large metal yardstick and box knife to cut it down to exactly 4" tall all around. That allows me to stack three flats of freight cars in one tote.

To go between the cars, I use pieces of fluted polypropylene which looks like corrugated cardboard but is made of plastic. It can be had in 4'x8' sheets from Home Depot for about $35, but if you wait until after election day you can sometimes find it in the form of discarded and abandoned political signs by the side of the road...

That too is cut into strips about 4" tall, and then I glue cheap felt to both sides. They fit between the cars and not only cushion them but also support the next flat of cars above them. Finally, I print a contents description on a piece of paper and laminate it and slide it inside the end of the box. I sometimes write notes in Sharpie on the label, and over time if I need to change it I just print and laminate another sheet. It's very simple.

For some cars that are safe to stack, I leave the cracker box full height. 

For inexpensive 027 cars, I can fit more into the boxes and I don't bother to separate them with anything. They don't really move around anyway, and after 40-50 years they already show signs of wear.

It takes a little time to do, but I find the system works for me. My O scale collector friends have basements filled with Lionel boxes of train cars, which preserves the "collector value" but makes it impossible to see what's inside. Others have walls of train storage shelves which look gorgeous but are way out of my price range. I am happy with my approach.