The big news being broken by mustache twins Matier & Ross today is a potential plan, unveiled in a closed-door meeting last week at City Hall, to drastically rethink the routing of Caltrain and the eventual hi-speed rail line so that it hugs the waterfront, passes by the Warriors Arena, and frees up the existing rail yard at 4th and King for future development. The idea would be to remove a large section of the 280 overpass as well, so that what is currently an industrial area cut through by a freeway would become a new neighborhood with big development potential.

The plan would call for a major, and extremely expensive track reroute and underground tunnel that would turn existing tracks at 22nd Street, taking them under the waterfront from there, along Third Street, past the new, 18,000 seat Warriors Arena — thereby eliminating more need for parking which is one of the arguments being levied by those shadowy opponents — and create a new joint Caltrain/Hi-Speed Rail/Muni station near AT&T Park.

The track would then go under SoMa more directly to the new Transbay Terminal at First and Mission, and this would replace the need to extend Caltrain tracks up 4th Street, which had the been the plan until now.

The map below shows the proposed new route. The section shaded in red shows where the 280 overpass and the Caltrain tracks beneath it would be demolished, making way for a more development-friendly "boulevard," like we now have along the Embarcadero and Octavia where other freeways were previously removed.


The plan won't be officially unveiled to the public for another month. And, because this is San Francisco, it will probably need a ballot measure attached to get public sign-off on whatever the eventual scheme is. And as the Business Times notes, the Mayor already suggested tearing down 280 north of Mariposa a couple years back, and the city was awarded a $1.7 million grant to study that idea.

Matier & Ross say the mayor is "moving fast" on this and that Caltrain may not be all that happy about it — especially because it means that connecting Caltrain to downtown will take that much longer than already anticipated. The tunnel they're talking about would require tunneling through landfill, not to mention underneath some expensive real estate around South Park, etc., so this won't be simple by any stretch.

Everyone agrees that this is a wildly expensive, multi-billion-dollar idea, but transit advocate Scott Wiener is saying it's "definitely worth studying," and when it comes to getting the rails into downtown, "we need to make sure ... we get it right."

Stay tuned as this gets hashed out over the next few months, and as everyone figures out if it's even remotely feasible.

Map via Google Earth