While not dark wood, I bought one of these to display my Lionel N&W 611 and like the look of it. The top is a bent piece of acrylic on the long sides up over the top, and the ends are added on. It doesn't distract from the look of the locomotive at all, and keeps the dust away. My only gripe is the wooden base seems slightly bowed up in the middle so the top doesn't fit tight down on the ends, but from 12" away you don't really notice.
https://www.ebay.com/itm/30-O-...p2057872.m2749.l2649