Will there be even more people coming to DC if high-speed rail becomes a reality? Who knows, but Union Station wants to be ahead of the curve and has a seven billion dollar plan to make it happen. Of course there's a slight hiccup since the president of the redevelopment group has suddenly resigned, but as soon as someone fills his shoes they can start trying to find financing for the project. The major refurbishment will allow for three times as many people to use the station as do now. Most of the expansion would be underground but would receive natural light from a glass-enclosed concourse.
Renderings from Akridge/Shalom Baranes and Amtrak via WaPo