North–South corridor – Blue Line
E635143
The North–South corridor – Blue Line is the principal and oldest line of the Kolkata Metro, running along the city’s north–south axis and serving as a major urban transit backbone.
All labels observed (2)
| Label | Occurrences |
|---|---|
| North–South corridor – Blue Line canonical | 1 |
| north–south (Line 1–Blue) | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T7015982 — 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: North–South corridor – Blue Line Context triple: [Kolkata Metro, lineColor, North–South corridor – Blue Line]
-
A.
Northwest–East Line
The Northwest–East Line is the primary rapid transit route of Baltimore's Metro SubwayLink system, running across the city from the northwest suburbs toward the eastern side.
-
B.
Blue Line
The Blue Line is one of the Montreal Metro’s rapid transit lines, running east–west to serve several central and northeastern neighborhoods of the city.
-
C.
Blue Line
The Blue Line is a major rapid transit route in Chicago that runs between O'Hare International Airport and the city's western suburbs via downtown.
-
D.
Blue Line
The Blue Line is one of the main lines of the Lisbon Metro system, serving key central and northern areas of Portugal’s capital city.
-
E.
Blue Line
The Blue Line is one of the primary routes of the MetroLink light rail system serving the St. Louis metropolitan area.
- 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: North–South corridor – Blue Line Target entity description: The North–South corridor – Blue Line is the principal and oldest line of the Kolkata Metro, running along the city’s north–south axis and serving as a major urban transit backbone.
-
A.
Northwest–East Line
The Northwest–East Line is the primary rapid transit route of Baltimore's Metro SubwayLink system, running across the city from the northwest suburbs toward the eastern side.
-
B.
Blue Line
The Blue Line is one of the Montreal Metro’s rapid transit lines, running east–west to serve several central and northeastern neighborhoods of the city.
-
C.
Blue Line
The Blue Line is a major rapid transit route in Chicago that runs between O'Hare International Airport and the city's western suburbs via downtown.
-
D.
Blue Line
The Blue Line is one of the main lines of the Lisbon Metro system, serving key central and northern areas of Portugal’s capital city.
-
E.
Blue Line
The Blue Line is one of the primary routes of the MetroLink light rail system serving the St. Louis metropolitan area.
- F. None of above. chosen
Statements (29)
| Predicate | Object |
|---|---|
| instanceOf | metro line ⓘ |
| hasAlternativeName |
Kolkata Metro Line 1
NERFINISHED
ⓘ
North–South Metro corridor NERFINISHED ⓘ |
| hasAxis | north–south ⓘ |
| hasCharacter |
at-grade
ⓘ
elevated ⓘ underground ⓘ |
| hasColor | blue ⓘ |
| hasCountry | India NERFINISHED ⓘ |
| hasElectrification | 750 V DC third rail ⓘ |
| hasLineNumber | Line 1 NERFINISHED ⓘ |
| hasLocale | Kolkata metropolitan area NERFINISHED ⓘ |
| hasOperator | Metro Railway, Kolkata NERFINISHED ⓘ |
| hasOwner | Metro Railway, Kolkata NERFINISHED ⓘ |
| hasRole | urban transit backbone of Kolkata ⓘ |
| hasSystem | Kolkata Metro NERFINISHED ⓘ |
| hasTrackGauge | broad gauge ⓘ |
| hasTransitType | metro ⓘ |
| isBackboneOf | Kolkata urban rail transit network NERFINISHED ⓘ |
| isOldestLineOf | Kolkata Metro NERFINISHED ⓘ |
| isPrincipalLineOf | Kolkata Metro NERFINISHED ⓘ |
| locatedIn |
India
ⓘ
Calcutta ⓘ
surface form:
Kolkata
West Bengal ⓘ |
| partOf | Kolkata Metro NERFINISHED ⓘ |
| serves |
central Kolkata
ⓘ
north Kolkata ⓘ south Kolkata NERFINISHED ⓘ |
| usesRollingStockType | electric multiple unit ⓘ |
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: North–South corridor – Blue Line Description of subject: The North–South corridor – Blue Line is the principal and oldest line of the Kolkata Metro, running along the city’s north–south axis and serving as a major urban transit backbone.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
north–south (Line 1–Blue)