These might include the creeping wooly yarrow, shorter bellflowers, dwarf daphne, creeping phlox, creeping thyme, Mouse-ear Coreopsis, and low New York Asters. Of course, most alpine and rock garden perennials also will work. One trick I learned with the Alberta spruces when they get too large is to prune off the lower branches. Don't worry if you don't have a great amount of space for a garden railway. Use the area that you have.
Some layouts are even suitable for decks with potted plants.