AC-4
E163093
AC-4 was a class of Southern Pacific Railroad articulated steam locomotives of the distinctive cab-forward design used primarily for heavy freight service over mountainous routes.
All labels observed (1)
| Label | Occurrences |
|---|---|
| AC-4 canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1422812 — 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-4 Context triple: [Southern Pacific Cab Forward locomotive, classificationBySP, AC-4]
-
A.
S-52
S-52 is an International Hydrographic Organization standard that defines specifications for the display and use of electronic navigational chart (ENC) data in electronic chart display and information systems (ECDIS).
-
B.
FV101 Scorpion
The FV101 Scorpion is a British light reconnaissance tank and combat vehicle known for its high speed, aluminum armor, and use as part of the CVR(T) family during the Cold War.
-
C.
Mogami class
The Mogami class was a group of Japanese World War II cruisers notable for their heavy armament, high speed, and controversial design that pushed the limits of naval treaty restrictions.
-
D.
USS Pampanito
USS Pampanito is a World War II-era Balao-class submarine preserved as a museum ship and memorial in San Francisco.
-
E.
DD-412
DD-412 was the hull number of USS Hammann, a Sims-class U.S. Navy destroyer that served in World War II and was sunk during the Battle of Midway.
- 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-4 Target entity description: AC-4 was a class of Southern Pacific Railroad articulated steam locomotives of the distinctive cab-forward design used primarily for heavy freight service over mountainous routes.
-
A.
S-52
S-52 is an International Hydrographic Organization standard that defines specifications for the display and use of electronic navigational chart (ENC) data in electronic chart display and information systems (ECDIS).
-
B.
FV101 Scorpion
The FV101 Scorpion is a British light reconnaissance tank and combat vehicle known for its high speed, aluminum armor, and use as part of the CVR(T) family during the Cold War.
-
C.
Mogami class
The Mogami class was a group of Japanese World War II cruisers notable for their heavy armament, high speed, and controversial design that pushed the limits of naval treaty restrictions.
-
D.
USS Pampanito
USS Pampanito is a World War II-era Balao-class submarine preserved as a museum ship and memorial in San Francisco.
-
E.
DD-412
DD-412 was the hull number of USS Hammann, a Sims-class U.S. Navy destroyer that served in World War II and was sunk during the Battle of Midway.
- F. None of above. chosen
Statements (38)
| Predicate | Object |
|---|---|
| instanceOf |
Southern Pacific Railroad locomotive class
ⓘ
steam locomotive class ⓘ |
| boilerPressure | approximately 210 psi ⓘ |
| brakeType | air brakes ⓘ |
| buildEndDate | 1928 ⓘ |
| builder | Baldwin Locomotive Works ⓘ |
| buildStartDate | 1928 ⓘ |
| configuration | 4-8-8-2 ⓘ |
| countryOfOperation |
United States of America
ⓘ
surface form:
United States
|
| cylinderArrangement | simple expansion ⓘ |
| cylinderCount | 4 ⓘ |
| designer | Southern Pacific Railroad ⓘ |
| designFeature | cab-forward design ⓘ |
| fleetNumbers |
Southern Pacific Cab Forward locomotive
ⓘ
surface form:
Southern Pacific 4100–4109
|
| fuelType | fuel oil ⓘ |
| gauge |
4 ft 8 1⁄2 in
ⓘ
standard gauge ⓘ |
| hasArticulationType | Mallet-type articulated ⓘ |
| locationOfCab | front of locomotive ⓘ |
| locomotiveType | articulated steam locomotive ⓘ |
| numberBuilt | 10 ⓘ |
| operator |
Southern Pacific Railroad
ⓘ
surface form:
Southern Pacific Lines
Southern Pacific Railroad ⓘ |
| powerType | steam ⓘ |
| preservedUnits | 0 ⓘ |
| primaryUse |
heavy freight service
ⓘ
mountainous routes ⓘ |
| railroadClass | AC ⓘ |
| railwayLineUsedOn | Southern Pacific Railroad ⓘ |
| reasonForCabForwardDesign | to reduce crew exposure to smoke in long mountain tunnels and snow sheds ⓘ |
| retirementPeriod | 1950s ⓘ |
| status | all units scrapped ⓘ |
| successorClass | AC-5 ⓘ |
| tractiveEffort | approximately 124300 lbf ⓘ |
| UICClassification | (2′D)D2′ ⓘ |
| usedFor |
freight trains over Donner Pass
ⓘ
freight trains over Siskiyou and other SP mountain districts ⓘ |
| whyteNotation | 4-8-8-2 ⓘ |
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-4 Description of subject: AC-4 was a class of Southern Pacific Railroad articulated steam locomotives of the distinctive cab-forward design used primarily for heavy freight service over mountainous routes.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.