The rendering shows temporary lane closures for initial excavation prior to installation of concrete decking.

I’ll cut right to the part of the new construction fact sheet for the Westside Subway Extension that will likely interest you most:

Construction Schedule

Construction timing for the Project is dependent upon how the funding package for the project comes together. Presuming that the environmental clearance process concludes in 2011 and funding is secured, final design and contractor selection processes would occur in 2012.

It is likely that early utility relocation work and removal of paleontological resources (fossils) below Wilshire Bl in the vicinity of the La Brea Tar Pits could start sometime in 2012, with heavier construction starting on tunnels and stations in 2013. If funding is secured to build the 9-mile extension all at the same time, construction along the entire alignment to the Westwood/VA Hospital could potentially be completed by 2022. In this case, several pairs of TBMs would be used, tunneling various segments of tunnel at the same time, with work proceeding on all stations simultaneously.

If the project must be built in phases, based on the adopted Metro Long Range Transportatation, the first phase would proceed west from the Wilshire/Western Station to approximately La Cienega and it could take until 2036 to complete subsequent construction phases to reach the Westwood/VA station.

Here’s the link for the rest of the six-page fact sheet that explains the basics of the construction process — how stations are excavated, tunnels are bored and what construction will look like above ground. (Click here for a printable pdf version).

As for the above timeline, this is exactly why the America Fast Forward program is so important. If Congress can be persuaded to change federal law, Metro hopes to use low-interest federal loans and other financing to build the subway extension all at once, as well as try to accelerate the construction of the dozen transit projects funded by Measure R.

As regular readers know, it’s very hard to say what Congress may do. The America Fast Forward program would make the feds a lender instead of simply a spender. But there’s currently an anti-spending craze in Washington that could greatly pare down federal spending on transportation. Loosely translated, that means building a subway in a quarter century or doing it all at once over the next decade.

Or, to put it another way, how does not having a good alternative to sitting in Westside traffic sound for another 25 years?