MBTA Green Line tunnels
E208324
The MBTA Green Line tunnels are the underground sections of Boston’s Green Line light rail system that carry trolleys beneath the city’s core, including the central subway downtown.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Central Subway in downtown Boston | 1 |
| MBTA Green Line tunnels canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1865492 — 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: MBTA Green Line tunnels Context triple: [MBTA Type 7 Light Rail Vehicle, networkCompatibility, MBTA Green Line tunnels]
-
A.
Ted Williams Tunnel (Boston)
The Ted Williams Tunnel in Boston is a major underwater highway tunnel beneath Boston Harbor that forms part of the city's Central Artery/Tunnel Project, commonly known as the Big Dig.
-
B.
MBTA Ashmont Branch
The MBTA Ashmont Branch is a rapid transit line of Boston’s Red Line that runs from JFK/UMass station through Dorchester to Ashmont, serving several southern neighborhoods of the city.
-
C.
MBTA Mattapan High-Speed Line
The MBTA Mattapan High-Speed Line is a light rail trolley service in the Boston area that operates historic PCC streetcars between Ashmont Station in Dorchester and Mattapan, serving communities including Milton, Massachusetts.
-
D.
MBTA Red Line
The MBTA Red Line is a major rapid transit line in the Boston metropolitan area that runs through key communities including Cambridge, connecting them to downtown Boston and other parts of the region.
-
E.
MBTA Lansdowne
MBTA Lansdowne is a commuter rail station in Boston, Massachusetts, serving the Framingham/Worcester Line near Fenway Park.
- 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: MBTA Green Line tunnels Target entity description: The MBTA Green Line tunnels are the underground sections of Boston’s Green Line light rail system that carry trolleys beneath the city’s core, including the central subway downtown.
-
A.
Ted Williams Tunnel (Boston)
The Ted Williams Tunnel in Boston is a major underwater highway tunnel beneath Boston Harbor that forms part of the city's Central Artery/Tunnel Project, commonly known as the Big Dig.
-
B.
MBTA Ashmont Branch
The MBTA Ashmont Branch is a rapid transit line of Boston’s Red Line that runs from JFK/UMass station through Dorchester to Ashmont, serving several southern neighborhoods of the city.
-
C.
MBTA Mattapan High-Speed Line
The MBTA Mattapan High-Speed Line is a light rail trolley service in the Boston area that operates historic PCC streetcars between Ashmont Station in Dorchester and Mattapan, serving communities including Milton, Massachusetts.
-
D.
MBTA Red Line
The MBTA Red Line is a major rapid transit line in the Boston metropolitan area that runs through key communities including Cambridge, connecting them to downtown Boston and other parts of the region.
-
E.
MBTA Lansdowne
MBTA Lansdowne is a commuter rail station in Boston, Massachusetts, serving the Framingham/Worcester Line near Fenway Park.
- F. None of above. chosen
Statements (51)
| Predicate | Object |
|---|---|
| instanceOf |
railway tunnel system
ⓘ
urban transit infrastructure ⓘ |
| connectsStation |
Arlington
ⓘ
Boylston ⓘ Copley ⓘ Government Center ⓘ
linked to:
Government Center area
Haymarket ⓘ Heath Street ⓘ Hynes Convention Center ⓘ Kenmore ⓘ Lechmere ⓘ Medford/Tufts ⓘ
linked to:
Tufts University Medford/Somerville campus
North Station ⓘ Park Street ⓘ Prudential ⓘ Science Park/West End ⓘ Symphony ⓘ Union Square ⓘ |
| constructionStart | 1895 ⓘ |
| electrification | overhead catenary ⓘ |
| fareSystem | proof-of-payment ⓘ |
| gauge | standard gauge ⓘ |
| includesSection |
Boylston Street subway
ⓘ
linked to:
Tremont Street subway
Central Subway ⓘ Kenmore subway ⓘ North Station–Lechmere viaduct approaches ⓘ Tremont Street subway ⓘ |
| locatedIn |
Boston
ⓘ
linked to:
Boston, Massachusetts
Massachusetts ⓘ United States ⓘ
linked to:
United States of America
|
| notableFeature | one of the oldest subway tunnels in North America ⓘ |
| openingDate | 1897 ⓘ |
| operator |
Massachusetts Bay Transportation Authority
ⓘ
linked to:
MBTA
|
| originalPurpose | to remove streetcar congestion from Boston streets ⓘ |
| owner |
Massachusetts Bay Transportation Authority
ⓘ
linked to:
MBTA
|
| partOf |
MBTA Green Line
ⓘ
Massachusetts Bay Transportation Authority ⓘ
linked to:
MBTA
|
| rollingStock | light rail vehicles ⓘ |
| safetySystem | signalized operation ⓘ |
| serves |
Allston
ⓘ
Back Bay ⓘ Boston downtown ⓘ Brookline ⓘ Cambridge ⓘ Fenway–Kenmore ⓘ |
| system |
MBTA subway
ⓘ
linked to:
Boston subway
|
| trackConfiguration | mostly double track ⓘ |
| usedBy |
Green Line B branch
ⓘ
Green Line C branch ⓘ
linked to:
Green Line C Branch
Green Line D branch ⓘ
linked to:
MBTA Green Line D branch
Green Line E branch ⓘ |
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: MBTA Green Line tunnels Description of subject: The MBTA Green Line tunnels are the underground sections of Boston’s Green Line light rail system that carry trolleys beneath the city’s core, including the central subway downtown.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: MBTA Green Line tunnels