It has come to this: The mighty iron horse is now the subject of an “exciting new leisure activity—garden railroading.” Garden railroading? Oh, I suppose it might scare the rabbits away, but could a garden railroad inspire such great literature as this, the exhilarating opening from the 1922 book Tom Swift and His Electric Locomotive: “‘An electric locomotive that can make two miles a minute over a properly ballasted roadbed might not be an impossibility,’ said Mr. Barton Swift ruminatively. ‘It is one of those things that are coming,’ and he flashed his son, Tom Swift, a knowing smile.” I don’t think so. Where once the majestic Superchief roared over the Rockies, and belching steam locomotives thundered across the plains, moving the people and goods of a vibrant nation, now miniature diesels toot-toot through the petunias. The hard evidence of America’s decline from a can-do country to a land of leisure-obsessed hobbyists will be on proud display at Greenberg’s Great Train and Collectible Toy Show. In addition to a variety of “dynamic operating layouts” and dealers, one may marvel at the Cactus Valley Railroad, an elaborate HO-scale setup by “one of our nation’s foremost model railroad craftsmen, Dave Frary.” I bet Frary wouldn’t have lasted a day shoveling coal on the Rock Island Line. If trains still mattered, you’d be advised to book one for the journey to the Capital Expo Center in the far hinterlands of Chantilly. From 11 a.m. to 5 p.m. Saturday, July 10, and 11 a.m. to 4 p.m. Sunday, July 11, at the Capital Expo Center, 4320 Chantilly Place, Chantilly. $5. (703) 802-0066. (Dave Nuttycombe)