The Rensselaer Model Railroad Society's famed 4,000-square-foot model train layout is breaking up again, this time for good.

This world, created by the Short Line Model Railroad Club of Ephrata, is frozen in time. Look closely and many of the tiny people are wearing shorts or playing a pick-up basketball game in T-shirts.

The business park exterior of the Twin City Model Railroad Museum in Saint Paul, Minnesota is fairly unremarkable. But once inside, visitors of all ages are in for a magical, immersive experience—the ...