AC-12
E172335
AC-12 was the final and most advanced class of Southern Pacific’s Cab Forward articulated steam locomotives, renowned for their powerful performance in heavy freight service over mountainous terrain.
All labels observed (1)
| Label | Occurrences |
|---|---|
| AC-12 canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T1422820 — 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-12 Context triple: [Southern Pacific Cab Forward locomotive, classificationBySP, AC-12]
-
A.
AC-11
AC-11 was a class of Southern Pacific Railroad cab-forward articulated steam locomotives designed for heavy freight service over mountainous routes.
-
B.
AC-10
AC-10 was a class of Southern Pacific Railroad cab-forward articulated steam locomotives built for heavy freight service over mountainous routes.
-
C.
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.
-
D.
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.
-
E.
AC-9
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.
- 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-12 Target entity description: AC-12 was the final and most advanced class of Southern Pacific’s Cab Forward articulated steam locomotives, renowned for their powerful performance in heavy freight service over mountainous terrain.
-
A.
AC-11
AC-11 was a class of Southern Pacific Railroad cab-forward articulated steam locomotives designed for heavy freight service over mountainous routes.
-
B.
AC-10
AC-10 was a class of Southern Pacific Railroad cab-forward articulated steam locomotives built for heavy freight service over mountainous routes.
-
C.
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.
-
D.
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.
-
E.
AC-9
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.
- F. None of above. chosen
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
Southern Pacific locomotive class
ⓘ
preserved steam locomotive ⓘ steam locomotive class ⓘ |
| boilerPressure | 250 psi ⓘ |
| brakeType | air ⓘ |
| buildEndDate | 1944 ⓘ |
| builder | Baldwin Locomotive Works ⓘ |
| buildStartDate | 1943 ⓘ |
| city |
Sacramento
ⓘ
surface form:
Sacramento, California
|
| class | AC-12 self-linksurface differs ⓘ |
| classPosition | final Cab Forward class on Southern Pacific ⓘ |
| country |
United States of America
ⓘ
surface form:
United States
|
| cylinderArrangement | simple articulated ⓘ |
| cylinderCount | 4 ⓘ |
| cylinderSize | 24 in × 32 in ⓘ |
| designer | Southern Pacific Railroad ⓘ |
| driverDiameter | 63 in ⓘ |
| feature |
articulated frame
ⓘ
cab located at front of locomotive ⓘ designed for long tunnels and snow sheds ⓘ |
| fuelType | bunker oil ⓘ |
| gauge | 4 ft 8½ in standard gauge ⓘ |
| historicalSignificance |
one of the most powerful steam freight locomotive classes on Southern Pacific
ⓘ
represents the peak of Southern Pacific Cab Forward development ⓘ |
| location | California State Railroad Museum ⓘ |
| locomotiveConfiguration | Cab Forward ⓘ |
| notableRoute |
Southern Pacific Donner Pass line
ⓘ
Southern Pacific Overland Route ⓘ Southern Pacific Siskiyou and Shasta routes ⓘ |
| powerType | steam ⓘ |
| predecessorClass | Southern Pacific AC-11 ⓘ |
| preservedLocomotive |
Southern Pacific Cab Forward locomotive
ⓘ
surface form:
Southern Pacific 4294
|
| preservedUnits | 1 ⓘ |
| primaryRouteType | mountainous terrain ⓘ |
| primaryService | freight ⓘ |
| railwayOperator | Southern Pacific Railroad ⓘ |
| reasonForCabForwardDesign | to reduce crew exposure to smoke in tunnels and snow sheds ⓘ |
| retirementPeriod | 1950s ⓘ |
| roadNumberRange | SP 4275–4294 ⓘ |
| status |
on static display
ⓘ
retired from regular service ⓘ |
| superheater | yes ⓘ |
| totalProduced | 20 ⓘ |
| tractiveEffort | approximately 124300 lbf ⓘ |
| UICClassification | (2′C)C2′ h4 ⓘ |
| valveGear | Walschaerts ⓘ |
| 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-12 Description of subject: AC-12 was the final and most advanced class of Southern Pacific’s Cab Forward articulated steam locomotives, renowned for their powerful performance in heavy freight service over mountainous terrain.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.