To resolve capacity issues, WMATA has proposed building a new Metro loop line through downtown. But there might be a better way to resolve those issues and make the current system more efficient at the same time.

New tunnels and realigning some Metro lines could increase capacity in the core. All images by the author.

While Metro’s solution will adequately address the capacity problems, it will do nothing to sort out the fundamental geometric problems with the way the system was set up to begin with.

Metro’s proposal overlays multiple U-shaped or loop lines through the core, widely acknowledged as one of the least efficient ways to organize rail transit networks. Instead, Metro should build to provide routes that hit major job centers & transfer points, travel from A to B as directly as possible, and minimize the merging of routes, or interlining.

An alternative approach would be to combine new capacity from south and east of downtown with the branches of the Red Line so trains can travel all the way through the core without looping back on themselves. I believe the proposal shown in the map below shows the most effective combination of these lines.

The tunnels to create this network would be as follows:

Another way for Metro to add capacity downtown.

1. Build a new approximately 3.5-mile M Street subway for the Orange and Blue lines from Rosslyn to Metro Center, with five new stations at Rosslyn, Georgetown, West End, Connecticut Avenue, and Thomas Circle

2. Build a new approximately 0.85-mile tunnel between McPherson Square and Judiciary Square to combine the existing Franconia-Springfield end of the Blue Line, the Huntington end of the Yellow Line, and the Glenmont branch of the Red Line into a new Red Line. This would include one new station under G Place between 9th and 10th streets and transfers to the Gallery Place and Metro Center stations.

3. Build a new approximately 1.65 mile tunnel under 4th and 6th Streets SW between Waterfront and Gallery Place to combine the existing Branch Avenue end of the Green Line and Shady Grove branch of the Red Line into a new Green line. This would include two new stations at Independence Ave and Constitution Ave and a transfer to the L’Enfant station.

Geographic detail of new tunnels downtown. Click to see an interactive map.

This work solves Metro’s core capacity problems, creates a more efficient system by straightening the Red Line’s branches, and reduces system-wide merges to a total of three, down from six.

It also does so while building fewer stations than Metro’s loop proposal, with eight instead of fifteen, and six miles of subway instead of eight. The express tracks along I-66 are not needed under either approach at current ridership, and could be built in a later phase.

Under this proposal, every branch of the network except the Greenbelt branch would pass through the city’s central business district around Farragut Square, whereas under Metro’s plan both the Greenbelt and Branch Avenue branches of the Green line will miss it.

If possible, the current track connections should be kept to allow for system redundancy in cases of maintenance or emergencies. The new platforms at Rosslyn and Pentagon should be designed to minimize transfer time, ideally with cross platform transfers. Because the line to Shady Grove has much higher ridership than the line to Branch Avenue, the system should be built to allow some trains to terminate at Independence Avenue and turn back north.

Metro could eventually provide additional service along I-66 and to Union Station, as shown in the long-term proposal below.

How new tunnels downtown could support future outward extensions.

Providing fully separate tracks for the Blue Line would achieve both objectives and provide operational independence for every line. Such a subway could be built following H Street and Constitution Avenue. It would form an east-west “express” route, relieving congestion at Union Station and on both the Orange and Red lines through downtown.

This long term plan would set the system up for additional extensions in Maryland and Northern Virginia. In addition, the burgeoning streetcar network and the circumferential Purple Line would supplement this network.

How Metro could expand with more capacity in the core.

Metro’s proposal and the one described in this post both provide for needed expansion to the system’s core and eliminate chokepoints, but do so in opposite ways. One interweaves lines together extensively, while the other reorganizes track connections to keep routes as operationally independent as possible.

This difference will have major effects on how a rider will navigate the system, where they will transfer, and how long it will take to get from A to B. I believe the proposal outlined here will create a much more intuitively navigated network with greater speed and reliability that better serves the future needs of the region.

Alex Barclay is an architect working in New York City. He grew up in San Antonio and received his Bachelors of Architecture from the University of Texas at Austin in 2005. He maintains an active interest in transportation and urban planning issues in New York and throughout the United States.