The Capitol Riverfront Business Improvement District hit the wires this morning with a study they’d commissioned on the economic impact of Metro’s Green Line (or at least the line’s midsection; it omitted the underperforming stations east of the Anacostia and in Prince George’s County). Despite its restricted scope—-and dubious premise of the Green Line being less respected than its Red and Orange siblings, which I’ve only seen among the Tea Party set—-the study showed impressive return on the region’s investment: During the 2000s, for example, the area within a quarter mile of the stations studied captured 32 percent of the entire growth of 18-24-year-olds in the District.

It’s easy to forget the pain the Green Line’s construction caused, though. From the Metro geek bible, The Great Society Subway:

When WMATA finally broke ground on the Green line, in August 1985, residents learned that the only thing worse than lack of construction was construction itself. With bedrock too deep below the surface to employ rock tunneling, WMATA engineers specified the same cut-and-cover construction that had proved so disruptive downtown and on Capitol Hill…Virginia Ali, whose Chili Bowl restaurant had served U Street since 1958, had endured riots and illicit drug markets, but subway construction was worse. With U Street itself blocked off, customers had to find their way through alleys. If construction workers hit a gas line, diners would have to evacuate, and frequently Ali found her restaurant’s floor inches deep in dirty water that ran off the wooden planks that served as U Street’s decking. A block-long stretch of 7th Street turned into a twenty-foot-deep garbage pit; residents fretted that children might climb through the shoddy fences and fall in. By the eve of completion, a neighborhood resident mourned, “after five years of construction, the name of the game right now is survival.”

Now, taking out 31 homes and 43 businesses is a different question entirely—-that’s what Montgomery County is saying will have to happen for the Purple Line to be built from New Carrollton to Bethesda. Losing your home is a lot worse than putting up with open pits for a few years. But the worse bad news, from the public at large’s perspective, is how long it could take to get all of those property owners to move. Eminent domain is a nasty business, as a new documentary about a Brooklyn megadevelopment details, and litigation could hold the process up for years.

Through what’s likely to be another long slog for the Purple Line, folks should keep in mind the lessons of the Green: Well-managed growth made possible by Metro stations can work wonders in the long term. Those houses that go will replaced by a whole lot more in the future.