AC-9
E168627
The AC-9 was a class of massive 2-8-8-4 articulated steam locomotives built for the Southern Pacific Railroad, notable for their conventional (non-cab-forward) design and use in heavy freight service.
All labels observed (1)
| Label | Occurrences |
|---|---|
| AC-9 canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1422817 — 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: AC-9 Context triple: [Southern Pacific Cab Forward locomotive, classificationBySP, AC-9]
-
A.
AC-8
AC-8 was a class of Southern Pacific Railroad articulated steam locomotives in the distinctive cab-forward configuration, used primarily for heavy freight service over mountainous routes in the early 20th century.
-
B.
AC-5
AC-5 was a class of Southern Pacific Railroad cab-forward articulated steam locomotives built in the late 1920s for heavy freight service over mountainous routes.
-
C.
C-9
C-9 is a mountain railway line of Madrid’s Cercanías commuter rail network that connects the city with the Sierra de Guadarrama, including the Puerto de Navacerrada and Cotos areas.
-
D.
Ramport Aero
Ramport Aero is the company responsible for managing and operating Zhukovsky International Airport near Moscow, Russia.
-
E.
C-7
C-7 is a commuter rail line in the Cercanías Madrid network that connects central Madrid with various suburban areas.
- 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: AC-9 Target entity description: The AC-9 was a class of massive 2-8-8-4 articulated steam locomotives built for the Southern Pacific Railroad, notable for their conventional (non-cab-forward) design and use in heavy freight service.
-
A.
AC-8
AC-8 was a class of Southern Pacific Railroad articulated steam locomotives in the distinctive cab-forward configuration, used primarily for heavy freight service over mountainous routes in the early 20th century.
-
B.
AC-5
AC-5 was a class of Southern Pacific Railroad cab-forward articulated steam locomotives built in the late 1920s for heavy freight service over mountainous routes.
-
C.
C-9
C-9 is a mountain railway line of Madrid’s Cercanías commuter rail network that connects the city with the Sierra de Guadarrama, including the Puerto de Navacerrada and Cotos areas.
-
D.
Ramport Aero
Ramport Aero is the company responsible for managing and operating Zhukovsky International Airport near Moscow, Russia.
-
E.
C-7
C-7 is a commuter rail line in the Cercanías Madrid network that connects central Madrid with various suburban areas.
- F. None of above. chosen
Statements (45)
| Predicate | Object |
|---|---|
| instanceOf |
Southern Pacific Railroad locomotive class
ⓘ
articulated locomotive class ⓘ steam locomotive class ⓘ |
| articulationType | Mallet-style articulated ⓘ |
| brakeType | air brakes ⓘ |
| buildDate | 1939 ⓘ |
| builder | Lima Locomotive Works ⓘ |
| category |
2-8-8-4 locomotives
ⓘ
Southern Pacific steam locomotives ⓘ articulated steam locomotives ⓘ |
| configuration | 2-8-8-4 ⓘ |
| countryOfOrigin |
United States of America
ⓘ
surface form:
United States
|
| coupling | Janney coupler ⓘ |
| cylinderArrangement | compound articulated ⓘ |
| cylinderCount | 4 ⓘ |
| designer | Southern Pacific Railroad ⓘ |
| designType |
conventional cab
ⓘ
non-cab-forward ⓘ |
| era | late steam era ⓘ |
| fleetNumbers | 3800–3811 ⓘ |
| fuelType | coal ⓘ |
| gauge | standard gauge ⓘ |
| hasWheelArrangement | Whyte notation 2-8-8-4 ⓘ |
| laterFuelType | oil ⓘ |
| manufacturerLocation | Lima, Ohio ⓘ |
| nickname | AC-9 class ⓘ |
| operator |
Southern Pacific Railroad
ⓘ
surface form:
Southern Pacific Lines
|
| powerType | steam ⓘ |
| primaryUse |
freight trains
ⓘ
heavy freight service ⓘ |
| railroadRegion |
Old West
ⓘ
surface form:
American West
United States of America ⓘ
surface form:
United States
|
| railwayCompany | Southern Pacific Railroad ⓘ |
| railwayOperator | Southern Pacific Railroad ⓘ |
| retired | 1950s ⓘ |
| scrapped | all units scrapped ⓘ |
| serviceType | road freight ⓘ |
| technology | superheated steam ⓘ |
| totalProduced | 12 ⓘ |
| tractionType | adhesion ⓘ |
| UICClassification | (1′D)D2′ ⓘ |
| usedFor | mountain grades freight ⓘ |
| usedOn |
Southern Pacific main line in California’s Central Valley
ⓘ
surface form:
Southern Pacific main lines
|
| whyNotable |
largest conventional steam locomotives on Southern Pacific
ⓘ
only 2-8-8-4 locomotives owned by Southern Pacific ⓘ |
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: AC-9 Description of subject: The AC-9 was a class of massive 2-8-8-4 articulated steam locomotives built for the Southern Pacific Railroad, notable for their conventional (non-cab-forward) design and use in heavy freight service.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.