Greater Greater Washington has recently been hosting a debate about the need for a more direct rail connection to Dulles Airport. Spencer Lepler has argued that Virginia should convert the W&OD trail to an interurban rail line providing express non-stop service to downtown Washington. In rebuttal, Matt Johnson has argued that the Silver Line is enough of an investment in the Dulles corridor, and that converting the W&OD trail would be impractical.

What if they’re both right?

There is a solution out there that would provide faster service to Dulles without requiring much new infrastructure: A skip-stop express. It would be possible for Metro to run express trains along the (soon to be) existing Silver Line route by simply not stopping at every station, as potentially illustrated here:

A potential skip-stop express to Dulles Airport. East of Rosslyn all trains would serve all stops, but west of Rosslyn the express would only stop at the highest-ridership stations.

True, there will be no express tracks on the Silver Line, but while that makes a skip-stop service more operationally difficult, it doesn’t necessarily preclude the option entirely. If cross-over tracks are provided at every station, local trains can pull onto the opposite track at any station in order to let express trains pass by. Doing so requires careful coordination and alert train operators, but it’s completely possible. The downside is that trains going in the non-peak direction may have to stop and wait between stations if a local has crossed over onto the opposite track, but it could be that the added peak-direction efficiency is worth the trade-off.

If such operational difficulties can be overcome, a skip-stop express would be a true win-win for both Spencer and Matt. It would provide a quick connection to the airport and a faster ride downtown for outer suburbanites (freeing up seats on local trains for closer-in passengers in the process), but wouldn’t require the kind of massive new investment that a whole second rail line would need. In fact, such a train would in all likelihood be even faster than a W&OD route, since it wouldn’t have to travel all the way south to Alexandria before crossing the Potomac.

If Metro can do this the region would get all the benefits of an express line without any of the headaches associated with the W&OD route. It would be a cheaper, faster, better alternative. There would be little downside.

Cross-posted to Greater Greater Washington.