Transbay Tube
E84112
The Transbay Tube is an underwater rail tunnel beneath San Francisco Bay that carries BART trains between San Francisco and Oakland.
All labels observed (7)
| Label | Occurrences |
|---|---|
| Transbay Tube canonical | 13 |
| BART Transbay Tube | 1 |
| Bay Area Rapid Transit tunnels | 1 |
| San Francisco–Oakland Transbay Tube | 1 |
| Transbay Tube (toward San Francisco) | 1 |
| Transbay corridor | 1 |
| Yerba Buena Tunnel | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T664113 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Transbay Tube Context triple: [BART, notableInfrastructure, Transbay Tube]
-
A.
Alameda Corridor
The Alameda Corridor is a 20-mile freight rail expressway in Los Angeles County that consolidates and streamlines cargo movement between the region’s ports and the national rail network.
-
B.
Metro C Line
The Metro C Line is a light rail line in Los Angeles County that runs east–west, connecting Norwalk to Redondo Beach and serving key transit hubs including Los Angeles International Airport via shuttle.
-
C.
Peninsula rail corridor
The Peninsula rail corridor is the major rail line running through California’s San Francisco Peninsula, carrying both commuter and intercity trains between San Francisco and the South Bay.
-
D.
San Mateo–Hayward Bridge
The San Mateo–Hayward Bridge is a major vehicular bridge in the San Francisco Bay Area that carries traffic across the bay between the San Mateo Peninsula and the East Bay.
-
E.
BART
BART (Bay Area Rapid Transit) is a major rapid transit system serving the San Francisco Bay Area, linking cities like San Francisco, Oakland, and Berkeley with surrounding suburbs and regional transit networks.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Transbay Tube Target entity description: The Transbay Tube is an underwater rail tunnel beneath San Francisco Bay that carries BART trains between San Francisco and Oakland.
-
A.
Alameda Corridor
The Alameda Corridor is a 20-mile freight rail expressway in Los Angeles County that consolidates and streamlines cargo movement between the region’s ports and the national rail network.
-
B.
Metro C Line
The Metro C Line is a light rail line in Los Angeles County that runs east–west, connecting Norwalk to Redondo Beach and serving key transit hubs including Los Angeles International Airport via shuttle.
-
C.
Peninsula rail corridor
The Peninsula rail corridor is the major rail line running through California’s San Francisco Peninsula, carrying both commuter and intercity trains between San Francisco and the South Bay.
-
D.
San Mateo–Hayward Bridge
The San Mateo–Hayward Bridge is a major vehicular bridge in the San Francisco Bay Area that carries traffic across the bay between the San Mateo Peninsula and the East Bay.
-
E.
BART
BART (Bay Area Rapid Transit) is a major rapid transit system serving the San Francisco Bay Area, linking cities like San Francisco, Oakland, and Berkeley with surrounding suburbs and regional transit networks.
- F. None of above. chosen
Statements (46)
| Predicate | Object |
|---|---|
| instanceOf |
subaqueous tunnel
ⓘ
transport infrastructure ⓘ underwater rail tunnel ⓘ |
| carriedTrafficType | rapid transit ⓘ |
| closureDurationAfter1989Earthquake | about one month ⓘ |
| connects |
Oakland
ⓘ
San Francisco ⓘ |
| constructionCost | hundreds of millions of US dollars (1970s) ⓘ |
| constructionMethod | immersed tube tunnel ⓘ |
| constructionStartDate | 1965 ⓘ |
| crosses | San Francisco Bay ⓘ |
| designedFor | earthquake resistance ⓘ |
| endPoint |
West Oakland area of Oakland
ⓘ
linked to:
West Oakland
|
| hasEmergencyWalkway | yes ⓘ |
| hasMaximumDepthBelowWaterSurface |
approximately 135 feet
ⓘ
approximately 41 meters ⓘ |
| hasSeismicRetrofit | yes ⓘ |
| hasSignalingSystem | automatic train control ⓘ |
| hasSpeedRestriction | yes ⓘ |
| hasSpeedRestrictionReason | noise and structural considerations ⓘ |
| hasStructureType | steel and concrete tube ⓘ |
| hasVentilationSystem | yes ⓘ |
| highestSpeedLimit |
approximately 130 km/h
ⓘ
approximately 80 mph ⓘ |
| isCriticalInfrastructureFor |
Transbay BART service
ⓘ
linked to:
BART
|
| isKeyLinkIn |
Transbay corridor
ⓘ
linked to:
Transbay Tube
|
| isOnlyRailLinkType | heavy rail transit between San Francisco and Oakland ⓘ |
| length |
approximately 3.6 miles
ⓘ
approximately 5.8 kilometers ⓘ |
| locatedIn |
California
ⓘ
linked to:
California, United States
San Francisco Bay ⓘ United States ⓘ
linked to:
United States of America
|
| numberOfTracks | 2 ⓘ |
| openedForService | September 1974 ⓘ |
| openingDate | 1974 ⓘ |
| operator | Bay Area Rapid Transit District ⓘ |
| ownedBy | Bay Area Rapid Transit District ⓘ |
| partOf |
BART system
ⓘ
linked to:
BART
|
| passesUnder |
San Francisco Bay shipping channel
ⓘ
linked to:
San Francisco Bay
|
| servesMetropolitanArea | San Francisco Bay Area ⓘ |
| startPoint |
Embarcadero area of San Francisco
ⓘ
linked to:
Embarcadero, San Francisco
|
| trackGauge |
1676 mm
ⓘ
5 ft 6 in ⓘ |
| usedBy |
BART trains
ⓘ
Bay Area Rapid Transit ⓘ
linked to:
BART
|
| wasClosedAfterEvent | 1989 Loma Prieta earthquake ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Transbay Tube Description of subject: The Transbay Tube is an underwater rail tunnel beneath San Francisco Bay that carries BART trains between San Francisco and Oakland.
Referenced by (19)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Transbay Tube
linked to: Transbay Tube
linked to: Transbay Tube
linked to: Transbay Tube
linked to: Transbay Tube
subject linked to:
Yellow Line
linked to: Transbay Tube