O-Divisadero: Loop Line Phasing

Phase 1 of the Loop line would bring Muni Metro service to the area North of Market between Transbay/Embarcadero Station on the edge of the San Francisco Bay and States/Castro Station at the base of Twin Peaks. I propose eight stations north of Market, plus two transfer stations to existing rail infrastructure at either end of the line. Alignment along Broadway allows use of the existing tunnel under Russian Hill to save costs; only the Van Ness - Alamo Square part of the alignment would require tunnel boring.

Phase 1 _ Broadway-Divisadero Subway
(view O-Divisadero in a larger map _ read methodology for proximal population statistics)

South of Market, the city is already served by several spans of Muni surface Light Rail (the J-Church and T-Third) as well as the Central Subway; additional service to Noe Valley, the Mission, SoMa and Rincon Hill would complete the Loop with 8 stations south of the slot (which would then share track with the G-Geary along Beale, through the Harrison street undercrossing and Transbay Station).

Phase 2 _ Mission-SoMa Subway
(view OLx-Loop Line in a larger map _ read methodology for proximal population statistics)

O-Divisadero: Central Loop Line

To complement the otherwise spoke-hub derived network of the Muni Metro system in San Francisco, a Loop line might be employed with transfers spaced evenly along the line to various trunks. This loop serves many of the primary tourist locations in the city (Columbus Ave / North Beach, Japantown Peace Plaza, Alamo Square / the Painted Ladies and the Haight) as well as a variety of quite populous residential areas (the central Van Ness corridor, Western Addition, Noe Valley, Mission, SoMa); the mix of users could assure high ridership year-around.

The northern component of the system serves the Financial Disctrict, Jackson Square, Nob- and Russian Hills, Japantown and Western Addition, Alamo Square, NoPa, the Haight and Corona Heights. The southern half runs through the Castro, Noe Valley, Mission Dolores and Liberty Hill, the Mission, Western and Central SoMa, South Beach, Rincon Hill and the Transbay District.

With the Central Subway providing Northwest-Southeast cross service, the Market Street Subway providing Northeast-Southwest connectivity and the G-Geary heading directly west from the Transbay Terminal, a robust skip stop transfer network could be achieved with a circular subway.

O-Divisadero Loop in the context of San Francisco's otherwise hub-and-spoke Metro System. (view mutative Muni Metro evolution)

G-Geary: Phasing of Northern San Francisco Subways

The Northern terminus of the T-Third line at Chinatown is a temporary condition: with the decision to terminate the Central Subway tunnel at Washington Square, not in Chinatown where the last operating station will be located, it is a logical deduction that Muni intends to continue Metro service to the Northern waterfront at some point in the future. Similarly, the transfer of Westbound proposed G-Geary passengers from Light Rail to Bus Rapid Transit (BRT) at Webster Station is a stop-gap measure, a condition to change once support for mass transit on Western Geary Boulevard strengthens.

Muni after construction of G-Geary Phase 1 and T-Third Phase 2. The (temporary) northern terminus of  the T-Third at Chinatown is made functional with transfer to the G; westbound traffic at Webster transfers to BRT below the aerial platform.

Ultimately, the T-Third will head north to Fisherman's Wharf at the very least; an alternative alignment proceeds through a number of stops along the Northern Waterfront and Russian Hill with a Western terminal at the Marina Green, thereby serving a much larger cross-section of the northern population.

Muni with G-Geary Phase 2 extension to Sutro Heights; T-Third Phase 3 to Fishermans Wharf and (speculative) Phase 4 to the Marina; F-Market extension through the Fort Mason tunnel and beyond to Chrissy Fields / Golden Gate. (view mutative Muni Metro evolution)

The G-Geary would ultimately continue through two more right-of-way-separated stations before becoming a streetcar on Geary Boulevard and continuing through the Inner and Outer Richmond districts to a terminus at Sutro Heights.

G-Geary: Clay-Geary Street Alignment

The 19th and 20th century hearts of San Francisco lie north of Market street; Jackson Square / the Barbary Coast districts were the historic center during the gold rush era and period of early growth, followed by Polk Street and the Tenderloin after the earthquake, and the Financial District and Union Square / Downtown in the modern era. Once it passes beneath the Market Street Subway, this proposal for a G-Geary train serves all of these areas as well as Cathedral Hill, Japantown and the Western Addition before running along the surface of Geary Boulevard in the Richmond District.

Sectional diagram of the Clay-Leavenworth-Geary Street Subway portion of the proposed G-Geary. South of Market the subway continues under Beale; West of Webster the alignment continues above grade, eventually becoming a Geary streetcar.

• The first stop is located under Clay Street at Sansome, on the north flank of the Financial District. This location counter-balances the strong transit presence on the southern side of this district (flanked by the Market Street Subway), and also provides right-of-way-separated access to Jackson Square and southern Columbus Avenue. The huge daily influx of workers to this district, home to all of San Francisco's Fortune 500 companies, makes it a natural fit for transit.
• Also under Clay, between Powell and Mason Streets lies the next station stop at Nob Hill, transfer point for the T-Third under Stockton Street at Chinatown. 
• By far the most populous part of San Francisco is the Tenderloin. If the rest of the city were equally populated, the City and County would boast over 1.6 million denizens overall. A metro station under Leavenworth between Sutter and Post would serve this district directly, with upwards of 17,500 people located within easy walking distance of the stop.
• After transitioning to a Geary Street alignment, the subway stops at Franklin,  serving the western edge of the Tenderloin and lower Polk along with the population on Cathedral Hill.
• Trains heading west transition to an aerial alignment at Laguna Street,  then stop between Fillmore and Webster Streets for their last Phase 1 station stop. Serving Japantown,  Fillmore and the Western Addition,  this station also allows for easy vertical connection for busses on the Geary bus rapid transit route.

G-Geary: Beale Street Alignment

South of Market Street near the verge of the San Francisco Bay lie the most quickly densifying neighborhoods in San Francisco, namely the Financial District South, the Transbay District (surrounding a transit terminal of the same name), and Rincon Hill.

The South-of-Market (SoMa) component of this proposal includes an alignment along Beale Street to serve these neighborhoods, with a station stop at the Transbay Terminal to tie CalTrain, AC Transit, Golden Gate Transit and others in the new intermodal Terminal to the Muni Metro and BART systems under Market Street; the alignment then continues south, with a station utilizing an existing cut under Harrison Street through Rincon Hill to keep cost of construction low, finally connecting the new FiDi South Subway to the Southern Embarcadero light rail corridor at the end of Beale, where trains can run along the surface to serve the existing Giants Stadium as well as the future Golden State Warriors Stadium on the waterfront.

Sectional diagram looking south and west from the new FiDi South Muni Metro alignment. North of Market the alignment continues into the Clay-Geary Subway; South of I-80 it joins the Southern Embarcadero 

• The location of the Transbay Muni Metro Station at Mission and Beale allows easy access from the east end of the Transbay Terminal mid-block on Beale between Howard and Mission, with pedestrian tunnels constructed alongside the subway tunnel under Beale Street to tie the Transbay cluster of services to existing and to-be-expanded BART and Muni Metro service at Embarcadero Station.
• A right-of-way separated surface station under the existing overpass at Harrison Street keeps construction costs relatively low, and allows for connections up to the flank of Rincon Hill, above, with its thousands of new housing units proposed and under construction. With more than half of a dozen proposed and under construction high-rises within a two block radius, the usage of this station could be staggering within a decade; the new MTC offices on Main would have their own transit stop. Potential use of the Bay Bridge Maintenance Facility just south of the overpass as Muni train maintenance and staging could be highly beneficial in such a central location.
• An additional line serving the Muni Metro Extension (MMX) along the Southern Embarcadero with service to the existing Giants and future Warriors Stadia would help alleviate overcrowding of the N-Judah trains during game periods.

G-Geary: Northern Subway in San Francisco

Many of San Francisco Municipal Railway's first established rail lines were along the Geary Street corridor; this major East-West axis in received early and heavy transit investment with the A-Geary-10th, B-Geary, C-Geary-California and D-Geary-Van Ness all in operation one hundred years ago. The corridor's current service (the 38-Geary cluster of busses) boasted over 55,000 daily boardings in 2007 — as real estate in eastern San Francisco continues to soar skyward, the western parts of this corridor are densifying and are ripe for the return of train service.

The G-Geary first phase subway connects Rincon Hill to the Financial District, Nob Hill, the Tenderloin and Japantown; the second phase extension continues with rail service to Western Addition/NoPa and the Richmond district.

This is a dream for rail service on the Geary Street Corridor. Stretching from the Rincon Hill, Transbay and FiDi South neighborhoods south of Market Street through downtown, Cinatown, Nob Hill and the Tenderloin to Japantown and the Western Addition, this alignment creates a skip-stop transfer network with the existing Market Street and currently under construction Central Subway. Utilizing an existing undercrossing through Rincon Hill and keeping the line shallow to allow cut-and-cover connection between the new Transbay station and Embarcadero keep the eastern alignment costs relatively low; a tunneling machine would be required only for the deep bore under Nob and Cathedral Hills, a tunnel which would serve three of the most densely populated and still densifying portions of the City of San Francisco, namely the Financial District, Chinatown/Downtown, and Nob Hill/Tenderloin/Polk Gulch.

Phase 1 / Subway

(view phase 1 G-Geary Subway in a larger map _ read methodology for proximal population statistics)


A scheme to provide Bus Rapid Transit (BRT) along the Geary Street corridor is currently in the planning stages, and hopefully opening for service before 2020. Terminating phase 1 rail constuction in an elevated station at Webster allows for vertical loading and unloading of trains from busses below, which with timed transfers which would speed movement from the Richmond District downtown hugely. When ready, phase 2 light rail could replace the BRT.

Phase 2 / Light Rail Transit

(view phase 2 GRx-Geary Richmond Extension in a larger map)

Methodology: Proximal Resident Population

To estimate the possible frequent use population incident on a station, I'm using data pulled from 2010 Census Block Groups within a 2-block radius of the center of the station. Take for example a proposed station centered at Leavenworth and Sutter streets in the TenderNob neighborhood of Downtown San Francisco.

First, locate the centerpoint of the station.

Next, draw a circle two blocks in radius (using streets not alleyways) along the major axis of the metro line at this point in its run (two blocks north and south along Leavenworth in this case).

Sum the population of all census block groups partially or completely encompassed by the circle.

In the case of this station, the following block groups are incident on the circle:
111bg2 - population 2,084
119.01bg1 - population 898
111bg3 - population 914
119.01bg2 - population 1,510
120bg1 - population 1,983
121bg1 - population 2,725
120bg2 - population 1,850
122.01bg1 - population 2,699
123.02bg1 - population 1,763
123.02bg1 - population 1,310
Population of proximal block groups — 17,736.

For the purposes of this comparison, an exact science is not what I'm looking for; after all it has been proven time and time again that "ridership estimations" are sorely lacking exactitude. Take, for example the BART SFO extension, originally estimated at 17,000 daily trips but only providing 20-30% of that amount in daily ridership during its first year of operation. Rather than try to divine how many people will use each station, I'm only identifying how many people are within an easily walkable distance (under seven blocks in this case) and could conceivably make use of the station with regularity.