Since the earliest days of Metro, planners and engineers have struggled with the idea of running the Blue Line between Rosslyn and Georgetown, but I believe that a solution to this problem could be found with looking at the problem in a roundabout way.
The problem of how to get the Blue line to have a stop in the heart of Georgetown has been the topic of discussion for a while now, and biggest obstacle has been how to navigate the extreme grades between Rosslyn and Georgetown.
Each area is perched atop significant bluffs above the Potomac below, making direct a tunnel between the two sides a nightmare, one that Metro abandoned in the earliest stages of planning as impracticable. The direct tunnel would have to descend and ascend such a steep grade over such a short distance so that a station at a practical depth would be impossible.
However, I propose a simple solution, simply make the distance between the stations longer and give the tunnel a little more room to make the descent. How can you do that when obviously you can't move the whole of Georgetown? Simply putting a big bend in the tunnel.
Railroad builders have used the technique of bending the tracks around bends, horseshoes and even loops to make the ascent of steep grades possible, such as at the famous Tehachipi Loop. The idea would be to give the train enough track to descend below the Potomac by bending the tracks to the west, making a turn under the Potomac and the C&O canal and making a gentle ascent under M Street NW. Certainly it would be more tunneling, but it would make the sorely needed station a possibility.
Could this work? Has anyone proposed something like this before?