Russel,
I've been using those "baseball card" boxes for years to transport trains to shows to run on my club's layout. Lots of room, inexpensive ,and when lined with paper towels, they provide a safe mode of transit. Some of them will even allow stacking of rolling stock in the slots. Since I recently put my trains in storage pending a move, many of my trains are stored this way. At least the ones that don't have the original factory boxes, like the older Gilbert trains. But those with old Gilbert boxes didn't have any padding or inserts to keep them from rolling around in the boxes, so they required paper towel wrapping to minimize "box rash".
