An Inevitable Metro Marriage: Blue and Yellow?

IN DOWNTOWN WASHINGTON, five Metorail lines run through what's essentially three tunnels. So sharing is crucial to make the system work. And as any commuter can tell you — especially those who live in the Orange Line's Ballston-Rosslyn corridor — sharing the tunnel that links Rosslyn with Capitol Hill via downtown with the Blue Line is not fun. While the prospect of a new crosstown M Street subway that separates Orange from Blue might be the infrastructure project transit geeks live for, anyone dealing with a budget knows that such an underground expansion is simply a fool's dream.

But can Metro separate the Orange and Blue lines without any new digging? The transit agency just did just that this past weekend, forced by a major track construction project at the Arlington Cemetery station that rerouted rail lines, as pictured at left. The Blue Line ran to Mount Vernon Square, where there is a pocket track for turn-backs.

Transit planners have toyed around with the idea of diverting trains originating at Franconia-Springfield away from Rosslyn by rerouting them into downtown via the Yellow Line bridge, relieving the pressure at Rosslyn.

It's just an idea, but as the Orange Line in Arlington County gets more and more crowded in coming years — and don't forget that the planned Tysons Corner rail extension will send more trains into the crowded downtown tunnel the Orange and Blue lines share — a major shift for Virginia commuters seems to be inevitable in the coming years.

Blog Rebuilding Place in the Urban Space has pondered the possibilities before and posts some maps and such for additional dream transit projects around the region.