Diving into some details about infill station locations, starting with the Blue and Yellow Line.

Franconia Road

The Virginia portion of the Blue Line features several long stretches without stations. Today’s Franconia-Springfield Station hyphenated after the system’s original plan to serve each location with a separate branch fell through.

The Blue Line follows the existing RF&P railroad corridor, first built in the 1870s. Today’s transit services are much newer – the Blue Line was extended to Van Dorn Street in 1991 and to Franconia-Springfield in 1997. VRE launched service in 1992 and added a station at Franconia-Springfield in 1995.

Aside from the Capital Beltway, the only street to cross the tracks between Van Dorn and Franconia-Springfield is Franconia Road, reflecting the age of the corridor.

Connections: Franconia Road sits more than a mile from Franconia-Springfield station and more than two miles from Van Dorn Street. Existing east-west travel in the area along Franconia Road provides potential for connecting transit and last-mile trips.

There is limited existing bus service across this stretch of Franconia Road, but adding a station here (and the potential connections it can offer) would open the door to a rider range of services.

Land use: The area is surrounded by mostly single-family residential uses (a combination of detached houses and townhouses), with a mix of auto-oriented retail and institutional buildings. Assuming that the residential uses are unlikely to change, the remaining areas offer only modest redevelopment potential.

The existing streetscape along Franconia Road itself isn’t friendly to walking. However, with modest suburban retrofits, this area could be transformed.

Ease of Construction: One potential benefit is that a station here ought to be easy (and cheap) to build. The WMATA tracks are straight as an arrow, with plenty of space between the CSX/VRE right of way and adjacent development. Adding side platforms to the existing rails ought to be a simple design.

Additionally, having platforms straddle Franconia Road’s overpass allows for headhouses along both the Eastbound and Westbound travel lanes, creating a chance for easy and direct bus connections.

Alternatively, the platforms could be entirely on one side of the overpass or another; there’s plenty of space. Likewise, if there’s a need to minimize vertical circulation to save cost, you could arrange to change the track geometry here to fit an island platform in. Point being – there are lots of options.

Eisenhower Valley

Eisenhower Valley is one of the areas where WMATA planned for a potential infill station from the start, preserving an area with sufficient space for a station, located near the eastern edge of the Alexandria rail yard.

The existing site has the right geometry for an island platform station – even the third rail is already positioned to the outside edge.

An alternative site is available closer to Telegraph Road, which offers better connections to existing development south of the tracks, as well as existing access to development in the Eisenhower East area of Alexandria via Mill Road.

This site is located along a four-track WMATA section – the two outer tracks serving the Blue Line, and two inner tracks feeding the Yellow Line from the Alexandria Yard.

Adding side platforms along the outer tracks should be relatively simple. Additionally, the warehouses immediately south of this location are owned by WMATA and potentially redundant facilities, as WMATA finishes work on their new Alexandria office building nearby.

Either location fills a lengthy gap on the Blue Line. Eisenhower Valley is nearly two route miles from Van Dorn Street and 4/5ths of a mile from King Street/Old Town. The alternative location is approximately 2,000 feet as the crow flies from the existing Eisenhower Yellow Line station.

Connections: Here’s the rub – without a much larger project, there aren’t many good connections here. Almost all travel in the area is east-west along either Eisenhower Ave or Duke Street. Adding a north/south street would be a big (and contentious) investment. Absent a major change to the street network, passengers on foot would either face a long walk to Duke Street, or force buses along Duke into a lengthy detour.

The alternative location has a better existing street network to build upon, including the potential Mill Road connection – but has the same issues connecting north across the tracks towards Duke Street.

Land Use: Most of the surrounding areas are commercial or light industrial uses, with some newer residential buildings included. However, the biggest parcels (like WMATA’s Alexandria Yard) aren’t redeveloping anytime soon – and I’m not holding out for Hong Kong-style platforms over rail yards, either.

To the north, the industrial uses could be redeveloped, but this area also includes several facilities critical to Alexandria’s operations, including their police HQ, DASH bus garage, and others.

The alternative location would be adjacent to existing and planned high rise development.

Ease of Construction: At the originally planned location, the station itself should be a breeze. Just add a platform – no track relocation required. It’s the additional projects that increase the complexity – do you add a roadway connecting north/south across all the rail tracks? What kind of redevelopment do you plan for?

Slaters Lane

The only underground infill station location on my initial list is Slaters Lane. The site is located along a short (~2,500′ long) duckunder tunnel, where the WMATA tracks dive beneath a rail spur that formerly provided rail access to Alexandria’s waterfront and a now-defunct coal-fired power plant, set to be redeveloped soon.

With the Potomac River Generating Station closed, the rail spur no longer has any customers. Sufficient space exists without existing structures to allow for a station platform.

Connections: There’s an opportunity to offer good transit connections at Slaters Lane. The site is close to the existing Metroway BRT, and potentially additional services that could make use of the Route 1 transitway.

Spacing to existing stations is appropriate – Slaters Lane is approximately 2,000 feet north of Braddock Road and ~4,000 feet south of the Potomac Yard infill station. Infill stations have the potential to make Metro a suitable option for travel within Alexandria itself, while the current network focuses mostly on regional travel.

A critical element will be providing for walking access on both sides of the RF&P tracks, either via an overpass or underpass.

Land Use: The big benefit of a station in this location is land use. The area west of the railroad tracks was part of the earlier phases of the long-term redevelopment of Potomac Yard, including a mix of mid-rise residential buildings and townhomes. Both Slaters Lane (to the east) and Monroe Ave (to the west) include commercial uses. And within a short walk of a future station, there are several potential redevelopment sites, including the now-closed power plant.

Ease of Construction: As I mentioned in the opening piece, my list of infill stations is almost exclusively above-ground locations. I’m not aware of any examples of building infill stations on an existing subway line without some kind of pre-existing design accommodation. Adding a connection to an existing, in-service rail tunnel is incredibly complex, expensive, and disruptive.

And yet, there are several reasons to include this location:

Shallow Tunnel: the existing tunnel was only put in place as a duck-under for the rail spur connecting the RF&P’s Potomac Yard to the Waterfront. The shallow design means only a small amount of excavation would be necessary.

Surface Conditions: the land atop the existing tunnel is either used as a roadway or open space, making an open-cut station design (similar to White Flint, Branch Avenue, Grosvenor-Strathmore, or Prince George’s Plaza) possible. Roadway reconfiguration would be required, adding to the project’s complexity.

Construction Methods: at the crayon level, the combination of surface conditions and shallow tunnel depth would make cut and cover construction feasible, potentially minimizing cost and complexity. Even if the final station design were underground, using cut and cover techniques on an open site is potentially beneficial.

Even so, this site is far more ambitious than any of the aboveground locations, and also risky.