Okay, so you built those fancy shelves and now display some 10,000 dollars worth of model trains. What about an earthquake or a tornado? After all, some folks do live in areas where such activities can and will occur. I mention this because most folks do not think about the unintended consequences of putting up shelves and watching their collections literally fall off. Thus rendering the shelves as useless.
Now in most instances, shelves work and please don't anyone take my commentary the wrong way here. Lets just say I am dubious about displaying such beautiful and expensive items like this because "STUFF" does happen and do you really want to take that chance? After all, many in here have very expensive collections.
One solution is too place a clear cover in front so that if the unthinkable happens, the cover may deter the trains from falling off the shelves. (Please see Eric's Trains). He did this primarily to keep his locomotives clean, safe and free from falling as well as children visiting and touching.
Again, in most instances, most do not deal with earthquakes or even tornadoes. Yet, we had an earthquake several years ago right here and it was enough to cause some damage to property and structures. So, my suggestion is place something in front of those expensive, irreplaceable and beautiful locomotives/trains when displaying them in this manner to ensure they will be secure and safe.
Otherwise, get real good home owners insurance that will cover these items.
Pete