SPUR recommends that we plan and build a new subway line through the South of Market area. It is probable that such a new subway line could be implemented incrementally, starting with the turnback, and would eventually link up with a second Transbay Tube to the East Bay. The new tube should accommodate four tracks in order to include BART and commuter rail.
SPUR believes that either Folsom or Townsend streets would be appropriate for the new alignment, although there are serious pros and cons of each. The new regional subway line should run under at least one of these two corridors.
I think "hell yeah" is the only appropriate response here. Especially since BART's consistent but not-entirely-believable excuse for why there is no late-night service is, "we only have one track, so we have to shut down the whole system to fix anything anywhere."