For those of you who want to navigate to Menards' O Gauge section without a direct link, all you have to remember is from the navigation pane, select [Home & Decor] - [Menards' Collectibles]. "O Gauge Train Stuff" is in its own pane on this page.
I don't live in their business footprint (I'm in NYC), but I have ordered three boxcars and the 24-flatcar case without incident. There might be isolated items that at some point in time are only available in-store, but I haven't ran into any.
---PCJ