AC-9 articulated steam locomotives
E905528
The AC-9 articulated steam locomotives were a small class of powerful, coal-burning 2-8-8-4 cab-forward-style engines built in the late 1930s for heavy freight service on the Southern Pacific Railroad, notable for being among the last and most distinctive articulated steam locomotives the railroad operated.
All labels observed (1)
| Label | Occurrences |
|---|---|
| AC-9 articulated steam locomotives canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T11105233 — 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 articulated steam locomotives Context triple: [Southern Pacific Railroad, notableLocomotiveClass, AC-9 articulated steam locomotives]
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A.
USRA 2-8-8-2 articulated locomotive
The USRA 2-8-8-2 articulated locomotive was a heavy freight steam engine design developed under the United States Railroad Administration during World War I, known for its powerful compound articulated configuration used by multiple American railroads.
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B.
USRA 2-6-6-2 articulated locomotive
The USRA 2-6-6-2 articulated locomotive was a standardized World War I–era American steam freight engine featuring a Mallet-type articulated wheel arrangement designed for heavy, slow freight service on steep grades and curving track.
-
C.
Forney locomotive
The Forney locomotive is a compact 19th-century steam tank locomotive type, notable for its rigid wheelbase and rear-mounted fuel and water tanks, widely used on urban elevated and commuter railways.
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D.
ACS-64 locomotives
ACS-64 locomotives are modern electric locomotives built by Siemens for Amtrak, designed for high-speed passenger service on the electrified portions of the U.S. Northeast Corridor.
-
E.
Super Power steam locomotive
The Super Power steam locomotive was an advanced, high-capacity steam engine design that significantly improved speed and efficiency in American railroading during the early 20th century.
- 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 articulated steam locomotives Target entity description: The AC-9 articulated steam locomotives were a small class of powerful, coal-burning 2-8-8-4 cab-forward-style engines built in the late 1930s for heavy freight service on the Southern Pacific Railroad, notable for being among the last and most distinctive articulated steam locomotives the railroad operated.
-
A.
USRA 2-8-8-2 articulated locomotive
The USRA 2-8-8-2 articulated locomotive was a heavy freight steam engine design developed under the United States Railroad Administration during World War I, known for its powerful compound articulated configuration used by multiple American railroads.
-
B.
USRA 2-6-6-2 articulated locomotive
The USRA 2-6-6-2 articulated locomotive was a standardized World War I–era American steam freight engine featuring a Mallet-type articulated wheel arrangement designed for heavy, slow freight service on steep grades and curving track.
-
C.
Forney locomotive
The Forney locomotive is a compact 19th-century steam tank locomotive type, notable for its rigid wheelbase and rear-mounted fuel and water tanks, widely used on urban elevated and commuter railways.
-
D.
ACS-64 locomotives
ACS-64 locomotives are modern electric locomotives built by Siemens for Amtrak, designed for high-speed passenger service on the electrified portions of the U.S. Northeast Corridor.
-
E.
Super Power steam locomotive
The Super Power steam locomotive was an advanced, high-capacity steam engine design that significantly improved speed and efficiency in American railroading during the early 20th century.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
Southern Pacific Railroad locomotive class
ⓘ
articulated locomotive class ⓘ steam locomotive class ⓘ |
| articulationType | Mallet-type articulated NERFINISHED ⓘ |
| assignedService |
El Paso–Carrizozo line
NERFINISHED
ⓘ
El Paso–Tucumcari line NERFINISHED ⓘ |
| brakeType | air brakes ⓘ |
| buildDate | 1939 ⓘ |
| builder | Lima Locomotive Works NERFINISHED ⓘ |
| cabLocation | rear ⓘ |
| configuration | 2-8-8-4 ⓘ |
| countryOfOrigin |
United States of America
ⓘ
surface form:
United States
|
| cylinderArrangement | compound articulated ⓘ |
| cylinderCount | 4 ⓘ |
| designedFor | long-distance freight over relatively flat territory ⓘ |
| designFeature |
cab-forward-style appearance
ⓘ
conventional boiler orientation (not true cab-forward) ⓘ |
| distinctFrom | Southern Pacific true cab-forward oil-burning classes NERFINISHED ⓘ |
| era | late steam era ⓘ |
| fleetNumbers | 3800–3809 ⓘ |
| followedByClass | Southern Pacific AC-10 NERFINISHED ⓘ |
| fuelType | coal ⓘ |
| gauge | standard gauge ⓘ |
| notableFor |
distinctive skyline casing
ⓘ
large 2-8-8-4 articulated design for freight ⓘ one of the few coal-burning articulated locomotives on Southern Pacific ⓘ |
| numberBuilt | 10 ⓘ |
| operator |
Southern Pacific Railroad
NERFINISHED
ⓘ
Texas and New Orleans Railroad NERFINISHED ⓘ |
| powerType | steam ⓘ |
| precededByClass | Southern Pacific AC-8 NERFINISHED ⓘ |
| preservedUnits | 0 ⓘ |
| primaryUse | heavy freight service ⓘ |
| railroad | Southern Pacific Railroad NERFINISHED ⓘ |
| railroadClass | AC-9 NERFINISHED ⓘ |
| railwayCompany | Southern Pacific Transportation Company NERFINISHED ⓘ |
| regionOfOperation |
American Southwest
NERFINISHED
ⓘ
New Mexico NERFINISHED ⓘ Texas NERFINISHED ⓘ |
| retirement | 1950s ⓘ |
| serviceEntry | late 1930s ⓘ |
| smokeboxLocation | front ⓘ |
| status | all units scrapped ⓘ |
| trackGauge | 4 ft 8 1⁄2 in ⓘ |
| UICClassification | (1′D)D2′ h4 ⓘ |
| usedFor | heavy coal and freight trains ⓘ |
| wheelArrangement | 2-8-8-4 ⓘ |
| whyNotable | among the last articulated steam locomotives operated by Southern Pacific Railroad ⓘ |
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 articulated steam locomotives Description of subject: The AC-9 articulated steam locomotives were a small class of powerful, coal-burning 2-8-8-4 cab-forward-style engines built in the late 1930s for heavy freight service on the Southern Pacific Railroad, notable for being among the last and most distinctive articulated steam locomotives the railroad operated.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.
subject surface form:
Southern Pacific Railroad