Originally Posted by bkong
If I remember correctly, the present tunnel under the Potomac is only one track and that's already a choke point with all the Orange and Blue trains during rush hour. What I read wasn't clear about how Metrorail might re-route Blue trains to the Yellow Line bridge across the Potomac. A majority of Virginian commuters who currently board the Blue Line in the mornings work in Northwest DC so they'd need to transfer at L'Enfant if their Blue trains take the Yellow Line bridge. Also, there'd need to be maintained a reasonable level of service to Arlington Cemetery.
My guess is also that any new tunnel would be at Georgetown. DC's a different city now and Georgetowners are really pining for a Metro station to the point that many of the merchants said they'd help pay for it, according to the Post a while back.
Don't forget all the commuters who work in Rosslyn, too... the blue line diversions will be quite a bother for them; I know a fair number of people just in my offices who take blue up from Alexandria who'd be pretty annoyed at having to go into DC and switch trains just to get to Rosslyn. A bunch more will start driving in to work, that's for sure. Didn't the planning folks decide about 5-7 years ago that they really needed to build another tunnel or bridge, but then some revised study claimed it wouldn't be needed for 20 years? Hindsight is always 20-20
Georgetown sure had better wake up and want Metro stop(s) soon... as it is, the traffic there is a nightmare, there's no parking, and that's outside of the busiest hours.