What are Metro's current and future below ground rail stations?
Current Underground Stations
- Metro A Line (Blue): 7th Street/Metro Center in downtown LA. Opened 1990
- Metro B/D Line (Red/Purple): Sixteen stations from Union Station to North Hollywood and Wilshire/Western Stations. Opened in phases 1993-2000
- Metro L Line (Gold): Two stations at Mariachi Plaza and Soto. Opened in phases 2003 and 2016
- Metro E Line (Expo): 7th Street/Metro Center Station in downtown LA. Opened 2012
Future Underground Stations
In addition, Metro currently has three projects under construction that incorporate underground stations:
- Metro Crenshaw/LAX Transit Project: Three underground stations at Expo/Crenshaw, Martin Luther King Jr. and Leimert Park.
- Metro Regional Connector: A fully underground alignment with stations at Little Tokyo/Arts District, Historic Broadway and Grand Avenue/Bunker Hill, and will connect to the existing 7th Street/Metro Center Station.
- Metro Purple (D Line) Extension Transit Project: Connecting at the existing Wilshire/Western Station, it adds stations at Wilshire/La Brea, Wilshire/Fairfax, Wilshire/La Cienega, Wilshire/Rodeo, Century City/Constellation, Westwood/UCLA and Westwood/VA Hospital.
Construction at each station is estimated to take five to seven years. Underground stations are constructed from the surface by excavating the area to be occupied by the station box. Construction staging areas are usually located immediately adjacent to station construction sites.
The combined staging area at each stations typically about one to three acres in size. The larger areas are needed where the tunnel boring machines (TBMs) are launched and/or the earth from the tunneling between the stations will be removed.
Building Underground Stations in Five Steps
Preparation typically begins with protecting or relocating any underground utilities, such as power lines, water lines, sewers, gas pipes, cable/telephone lines and storm drains. This will likely require temporary closures of portions of the street and detouring traffic around the work site. Detours are often limited to weekends or non-peak periods.
Piling & Deck Installation
The next step is to install concrete decking that serves as the temporary street surface, allowing traffic to continue to flow while construction continues underneath. The number of traffic lanes will be reduced, making space for the equipment and work area.
Excavation & Tunneling
Once the concrete decking is in place, the traffic continues to flow above while station construction continues below. The next steps involve removing the earth within the area that will eventually become the station box.
Once excavation is completed, construction of the inside of the station begins. The public areas of the subway stations also contain architectural design treatments and art work, information displays, lighting, signage, security monitoring devices and many other design elements.
One of the final steps in the process is the removal of the decking and restoration of the street. This can again be done at night and on weekends, or over a shorter period by closing the street continuously. When construction is finished, there is little evidence on the surface other than the station entrances.
What are some examples of construction impacts and mitigations?
Some of the impacts from subway construction could be:
- Noise, dust, vibration or visual appearance of construction sites
- Noise and vibration from below-ground construction activities
- Traffic impacts from temporary street closures
- Impacts to merchants near construction sites
- Traffic or other impacts from trucks hauling equipment to, or dirt from, construction sites
The Final Environmental Impact Statement (FEIS) and/or Final Environmental Impact Report (FEIR) will provide information about how the subway will be built, including impacts from construction and mitigations to eliminate or reduce these impacts, such as:
- Restrictions on days and hours of construction
- Identifying detours for any street closures
- Specifying truck haul routes
- Utilizing noise dampening and/or decorative fencing around construction sites
- Assistance to area business, etc