T Third Street

T Third Street
Northbound T-Third train passing Mission Rock station, April 2018.
Overview
Owner	San Francisco Municipal Transportation Agency
Locale	San Francisco, California
Termini	West Portal Sunnydale
Stations	30
Service
Type	Light rail
System	Muni Metro
Operator(s)	San Francisco Municipal Railway
Daily ridership	40,600 (2019; combined with K Ingleside)[1]
History
Opened	January 13, 2007 (2007-01-13) (limited service) April 7, 2007 (2007-04-07) (full service)[2]
Technical
Track gauge	4 ft 8+1⁄2 in (1,435 mm) (standard gauge)
Electrification	Overhead lines, 600 V DC
Route diagram Legend Sign change from (inbound) West Portal Forest Hill Twin Peaks Tunnel under Twin Peaks Castro Church Van Ness Civic Center Powell Union Square/​Market Street Central Subway ( opens 2022 ) Montgomery Embarcadero BART to Oakland MMX turnbacks Sign change to (outbound) Folsom Brannan 2nd and King Central Subway 2022 San Francisco 4th and King 4th Street Bridge Mission Rock UCSF/Chase Center Mariposa Mission Bay Loop 20th Street 23rd Street   Muni Metro East Yard   Marin Street Levon Hagop Nishkian Bridge over Islais Creek Evans Hudson/Innes Kirkwood/La Salle Oakdale/Palou Revere/Shafter Williams Armstrong wye Carroll Gilman/Paul Le Conte US 101 Caltrain Arleta Sunnydale Bayshore proposed Caltrain to San Jose This diagram: view talk

The T Third Street is a Muni Metro line in San Francisco, California. It is the first new light rail line in San Francisco in more than half a century, and the first fully accessible line in the system. It is also the first true light rail line in the mostly streetcar Muni Metro system, as it operates mostly in a street median, rather than in mixed traffic.

Route description[]

Testing on the line took place in summer 2006,^[3] with limited service starting on January 13, 2007, and full service beginning on April 7, 2007.^[4] It runs along the newly constructed light-rail tracks on Third Street and Bayshore Boulevard in the Visitacion Valley, Bayview/Hunters Point, Dogpatch, and Mission Bay neighborhoods, connecting to the existing Muni Metro system along the southern Embarcadero and below Market Street, and replaced the 15 Third bus line.

In the future, the line may be extended to Caltrain's Bayshore Station (to which it was originally planned to run) and, in the other direction, to San Francisco's Washington Square in North Beach via Chinatown Central Subway alignment.

Operation[]

Play media

The destination sign of an inbound Muni Metro K train changed from K Ingleside to T Third Street at West Portal Station.

The T Third operates seven days a week, beginning at 5 a.m. weekdays, 6 a.m. Saturdays and 8 a.m. Sundays, operating until 1 a.m. Service is provided by overnight Owl buses during the hours that rail service is not running. The N Owl serves the portion between Embarcadero and 4th Street, and the 91 Owl serves the portion between 4th Street and Sunnydale. On weekends, T Third Street Bus service runs from 5am until the start of rail service. The bus line largely follows the rail line, but it uses surface streets to parallel sections where the rail line has dedicated rights-of-way.

Routing description[]

Leaving the Market Street subway at Ferry Portal heading south, the T Third follows The Embarcadero south of Market Street, then veers onto King Street in front of Oracle Park until it reaches the Caltrain station terminal. This portion of the Muni Metro rail line between the Embarcadero portal and the Caltrain terminal was built in 1998 and is utilized by an extension of the N Judah, which shares track with the T to the Caltrain terminal at 4th and King. From there the T turns south on Fourth Street, crossing the bridge over Mission Creek before joining Third Street for the majority of the route's length. It passes through Mission Bay where the UCSF Mission Bay branch is located, then continues on south through the Bayview and Hunters Point neighborhoods. At the intersection of Third and Jamestown Avenue, the T continues to run in both directions as it crosses U.S. Highway 101 (James Lick Freeway), although only Third Street is open to auto traffic northbound; likewise, southbound auto traffic is splintered to a southbound on ramp to Highway 101 and merges with San Bruno Avenue. From there the T follows Bayshore Boulevard (changed over from Third) for two more stations until it reaches its terminus at Sunnydale Station. A section of track follows one more block until stopped short at the Daly City limits.

The T Third also uses the Muni Metro terminology in which an inbound train goes from West Portal to Embarcadero. This also means that an outbound T Third train runs from Sunnydale and out to the western neighborhoods via downtown.^[5] This is the reverse of other lines, as those lines have their outer termini on the southwest and west sides of the city, and those trains enter the subway from the west going inbound toward downtown.

History[]

Current route[]

T Third Street train serving Castro station in 2013.

T Third Street service was initially operated between Castro station and Sunnydale station. Following service changes on June 30, 2007, the T Third Street and the K Ingleside lines were interlined through the Market Street subway and Twin Peaks tunnels, resulting in a combined route from Balboa Park, through downtown, to the Visitacion Valley neighborhood.^[6]

Later changes . . .[]

The underground section of the line was closed west of Castro station from June 25 to August 24, 2018, due to the Twin Peaks Tunnel shutdown.^[7] On August 25, 2018, at the conclusion of the shutdown, Muni began running permanently two-car trains on the K/T line (as had been used east of Castro during the shutdown).^[8]

The line was shut down again, from January 22, 2019, until April 1, 2019, for construction of a new platform at UCSF/Mission Bay station.^[9][10]

In April 2019, the SFMTA ended the use of unscheduled short turns. These had been used to provide more consistent service on the inner portion of the line, but had caused inconsistent and less frequent service in the Hunters Point-Bayview and Visitacion Valley neighborhoods.^[11]

On March 30, 2020, Muni Metro service was replaced with buses due to the COVID-19 pandemic.^[12] Rail service returned on August 22, with the routes reconfigured to improve reliability in the subway. T Third Street and M Ocean View light rail lines were interlined, running between Sunnydale station and Balboa Park station.^[13] Light rail service was re-replaced with buses on August 25 due to issues with malfunctioning overhead wire splices and the need to quarantine control center staff after a COVID-19 case.^[14]

Rail service resumed on the Embarcadero–Sunnydale section of the T Third Street line on January 23, 2021.^[15] In preparation for the return of rail service, several temporary changes were made at the 4th Street bridge over China Basin: one southbound lane became a transit-only lane, and a northbound turn lane at Berry (which shared space with the tracks) was removed.^[16] This change was found to decrease delays at the bridge by 60%.^[17]

Service was re-extended to West Portal on May 15, again through-routed with the K Ingleside.^[18]

Central Subway[]

Central Subway construction at the south portal in December 2017.

T-Third has been built in phases. The second phase, currently under construction, is also known as the Central Subway project, and will reroute T-Third north of the 4th and King Station. The future alignment once the second phase is complete will neither share right-of-way with, nor share identities with the K Ingleside, avoiding both King Street and the congested Market Street subway.

Future routing description[]

The southern segment from Sunnydale to 4th and King Street will remain as-is, operating on street-level tracks in the median of Third Street and Bayshore Boulevard. After 4th and King, the line will cross King Street instead of turning onto it, and proceed to a new 4th and Brannan Station, and the line will then burrow to subsurface level at Bryant Street Portal, near where 4th passes under Interstate 80.^[19] Underground, the line will continue under Fourth Street, to Yerba Buena/Moscone Station, and then, after crossing Market Street, will turn slightly to continue under Stockton Street, continuing to Union Square/Market Station providing a transfer to Market Street subway MUNI and BART lines before running underneath Stockton Street and terminating at Chinatown Station.^[19]

Mission Bay Loop construction in August 2019.

Mission Bay Loop[]

The Mission Bay Loop project, which added a short turn loop using 18th, Illinois, and 19th, was constructed to supplement the Central Subway project. The loop was originally designed in 1998 as part of the Third Street Light Rail project, but was deferred due to insufficient funding. A $3.5 million construction contract was issued in 2014.^[20] Construction started in July 2016 and was completed in 2019.^[21] When the Central Subway is complete, Muni intends to split the T Third service into short-line and long-line services.^[22][23] The short-line service would run from Chinatown station to the Mission Bay Loop with 4-minute headways, while the long-line service would run the full route from Chinatown to Sunnydale station at 7.5-minute headways.^[22] Another loop at 25th and Illinois is proposed to increase short-line service frequency between Downtown and Dogpatch.^[24]

The proposed Third and Fourth phase of the Central Subway Project[]

A proposed third phase would build an extension beyond Chinatown, including new stations at Washington Square in North Beach and Fisherman's Wharf.^[19] In preparation, the tunnels were bored past Chinatown Station, and the tunnel boring machines were extracted from the intersection of Powell and Columbus, near Washington Square.^[25][26] The SFMTA published a concept study in January 2015 on the feasibility of several options for phase 3.^[26] The report studied three main alignments: Columbus Ave, Powell St, or a loop line on Powell St, Beach St, and Columbus Ave. Both subway and surface options were studied for each alignment. The report found that the phase 3 project could improve transit trip time by at least 50% and would increase the ridership on the T Third by 55%. Project cost estimates ranged from $440 million to $1.4 billion depending on the design. In June 2018, the SFMTA began a detailed study of possible routes to narrow down options for a future environmental impact study.^[27]

A conceptual fourth phase has been advanced by SFMTA and transit advocates to further extend the line west of Fisherman's Wharf to the Presidio.^[28][26] However, since the Central Subway station platforms will be about 250 feet (76 m) long, enough to accommodate two-car trains, unlike the upper deck Market Street subway platforms which can accommodate four-car LRV trains, the projected ridership increase with a fourth phase Presidio extension would require the stations currently under construction to be rebuilt to three- or four-car trains.^[26]

Diagrams of the various T Third Street routings over its history:

v t Initial alignment           Castro Church ← │ ↕ Van Ness Civic Center Powell Montgomery Embarcadero The Embarcadero and Folsom I-80 Bay Bridge The Embarcadero and Brannan 2nd and King Caltrain 4th and King 4th Street Bridge Mission Rock UCSF/Chase Center Mariposa Mission Bay Loop 20th Street 23rd Street   Muni Metro East Yard   Marin Street Levon Hagop Nishkian Bridge over Islais Creek Evans Hudson/Innes Kirkwood/La Salle Oakdale/Palou Revere/Shafter Williams Armstrong wye Carroll Gilman/Paul Le Conte US 101 Caltrain Arleta Sunnydale v t 2007–2021 Inbound: sign change from or West Portal Forest Hill Twin Peaks Castro Church ← │ ↕ Van Ness Civic Center Powell Montgomery Embarcadero Outbound: sign change to The Embarcadero and Folsom I-80 Bay Bridge The Embarcadero and Brannan 2nd & King Caltrain 4th and King 4th Street Bridge Mission Rock UCSF/Chase Center Mariposa Mission Bay Loop 20th Street 23rd Street   Muni Metro East Yard   Marin Street Levon Hagop Nishkian Bridge over Islais Creek Evans Hudson/Innes Kirkwood/La Salle Oakdale/Palou Revere/Shafter Williams Armstrong wye Carroll Gilman/Paul Le Conte US 101 Caltrain Arleta Sunnydale v t 2022– Provision for future extension to North Beach and the Presidio Chinatown Powell–Mason & Powell–Hyde California Street Union Square/​Market Street Powell Yerba Buena/​Moscone I-80 Central Subway 4th and Brannan original routing Caltrain 4th and King 4th Street Bridge Mission Rock UCSF/Chase Center Mariposa Mission Bay Loop 20th Street 23rd Street   Muni Metro East Yard   Marin Street Levon Hagop Nishkian Bridge over Islais Creek Evans Hudson/Innes Kirkwood/La Salle Oakdale/Palou Revere/Shafter Williams Armstrong wye Carroll Gilman/Paul Le Conte US 101 Caltrain Arleta Sunnydale Notes E Embarcadero began service in 2015

Route for the second phase (under construction as the Central Subway), planned route for third phase (extension to Fisherman's Wharf), and proposed routes for fourth phase (extension to the Presidio of San Francisco)

Station listing[]

All stations along this line feature high platforms, eliminating the need for the raising and lowering of entrance and exit steps characteristic of other Muni Metro lines. Stations south of Fourth and King feature short platforms that accommodate only two-car trains.

Station	Neighborhood	Other Muni Metro lines	Notes and Connections
West Portal	West Portal		Eastbound Ingleside trains become Third Street Muni: 48, 57 (Outbound terminus)
Forest Hill	Forest Hill and Laguna Honda		Muni: 36, 43, 44, 52
Castro	Castro		Market & Wharves Muni: 24, 35, 37
Church	Duboce Triangle, Mission Dolores		Market & Wharves Muni: 22, 37 ( Church stops at street level)
Van Ness	Mid-Market, Civic Center and Tenderloin		Market & Wharves Muni: 6, 7, 9, 9R, 47, 49, 79X, 90
Civic Center			BART Market & Wharves Muni, AC Transit, Golden Gate Transit, SamTrans (detailed list on station page)
Powell			BART Market & Wharves Powell-Hyde, Powell-Mason Muni, AC Transit, Golden Gate Transit, SamTrans (detailed list on station page)
Montgomery	Financial District		BART Market & Wharves Muni, Golden Gate Transit, SamTrans (detailed list on station page)
Embarcadero			Northbound Third Street trains become Ingleside BART Market & Wharves California St ⛴ Golden Gate Ferry, San Francisco Bay Ferry (at Ferry Building) Muni, Golden Gate Transit, SamTrans, PresidiGo (detailed list on station page)
Folsom	South Beach		Embarcadero
Brannan			Embarcadero
2nd and King	Mission Bay		Embarcadero Serves Oracle Park
4th and King			Embarcadero Caltrain Muni: 10, 30, 45, 47, 81X, 82X, 83X Flixbus
Mission Rock
UCSF/Chase Center			Serves the UCSF Mission Bay Campus and Chase Center Muni: 15, 22, 78X, 79X
UCSF Medical Center
20th Street	Dogpatch		Muni: 15, 48, 55
23rd Street
Marin Street	Bayview
Evans			Muni: 15, 19, 44
Hudson/Innes			Muni: 44, 54
Kirkwood/La Salle			Muni: 54
Oakdale/Palou			Muni: 15, 23, 24, 44, 54
Revere/Shafter			Muni: 54
Williams			Muni: 54
Carroll
Gilman/Paul			Muni: 29
Le Conte
Arleta	Visitacion Valley		Muni: 8, 8AX, 8BX, 9, 9R, 56 SamTrans: 292, 397
Sunnydale			Muni: 9, 9R SamTrans: 292, 397 (Inbound terminus)

Future[]

When these stations open in 2022, the T Third line will drop the portion of the line between West Portal and 2nd and King, and will no longer be interlined with K Ingleside.

Station	Neighborhood	Other Muni Metro lines	Notes and Connections
Chinatown	Chinatown		(Future northbound terminus)
Union Square/​Market Street	Financial District		BART Market & Wharves Powell-Hyde, Powell-Mason Serves Union Square Underground connection to Powell Street station
Yerba Buena/​Moscone	SoMa		Serves Yerba Buena Center for the Arts and Moscone Center
4th and Brannan

References[]

External links[]

Media related to T Third Street at Wikimedia Commons

• SFMTA - K Ingleside/T Third Street
• Wilbur Smith Associates (1993). Bayshore Transit Study (Report). City and County of San Francisco, San Francisco Municipal Railway. Retrieved 10 March 2017.
• "Central Subway Extension: Phase III of the T Third Rail project". San Francisco Municipal Transit Agency. Retrieved 24 October 2018.