Southern Pacific AC-6
E693824
The Southern Pacific AC-6 was a class of massive articulated cab-forward steam locomotives used by the Southern Pacific Railroad, notable for their distinctive design optimized for long mountain tunnels and heavy freight service.
All labels observed (3)
| Label | Occurrences |
|---|---|
| Southern Pacific AC-6 canonical | 2 |
| Southern Pacific AC-5 | 1 |
| Southern Pacific AC-6 class | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T7791080 — 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: Southern Pacific AC-6 Context triple: [AC-7, precededByClass, Southern Pacific AC-6]
-
A.
Southern Pacific AC-7
The Southern Pacific AC-7 was a class of massive articulated cab-forward steam locomotives used by the Southern Pacific Railroad, notable for hauling heavy freight over steep mountain grades in the early 20th century.
-
B.
Southern Pacific AC-11
The Southern Pacific AC-11 was a class of massive articulated cab-forward steam locomotives used by the Southern Pacific Railroad, primarily designed for heavy freight service over steep mountain grades.
-
C.
Southern Pacific AC-9
The Southern Pacific AC-9 was a class of massive articulated 2-8-8-4 steam locomotives built in the late 1930s for the Southern Pacific Railroad, primarily used for heavy freight service across challenging western routes.
-
D.
Southern Pacific GS-4
The Southern Pacific GS-4 is a class of streamlined 4-8-4 "Northern" steam locomotives built in the 1940s for the Southern Pacific Railroad, renowned for their distinctive orange and red "Daylight" livery and high-speed passenger service.
-
E.
Southern Pacific GS-3
The Southern Pacific GS-3 was a class of streamlined 4-8-4 "Northern" type steam locomotives built in the late 1930s for high-speed passenger service on the Southern Pacific Railroad.
- 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: Southern Pacific AC-6 Target entity description: The Southern Pacific AC-6 was a class of massive articulated cab-forward steam locomotives used by the Southern Pacific Railroad, notable for their distinctive design optimized for long mountain tunnels and heavy freight service.
-
A.
Southern Pacific AC-7
The Southern Pacific AC-7 was a class of massive articulated cab-forward steam locomotives used by the Southern Pacific Railroad, notable for hauling heavy freight over steep mountain grades in the early 20th century.
-
B.
Southern Pacific AC-11
The Southern Pacific AC-11 was a class of massive articulated cab-forward steam locomotives used by the Southern Pacific Railroad, primarily designed for heavy freight service over steep mountain grades.
-
C.
Southern Pacific AC-9
The Southern Pacific AC-9 was a class of massive articulated 2-8-8-4 steam locomotives built in the late 1930s for the Southern Pacific Railroad, primarily used for heavy freight service across challenging western routes.
-
D.
Southern Pacific GS-4
The Southern Pacific GS-4 is a class of streamlined 4-8-4 "Northern" steam locomotives built in the 1940s for the Southern Pacific Railroad, renowned for their distinctive orange and red "Daylight" livery and high-speed passenger service.
-
E.
Southern Pacific GS-3
The Southern Pacific GS-3 was a class of streamlined 4-8-4 "Northern" type steam locomotives built in the late 1930s for high-speed passenger service on the Southern Pacific Railroad.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
articulated locomotive class
ⓘ
steam locomotive class ⓘ |
| boilerPressure | 250 psi ⓘ |
| brakeType | air brakes ⓘ |
| buildDate | 1930 ⓘ |
| buildEndDate | 1930 ⓘ |
| builder | Baldwin Locomotive Works ⓘ |
| buildStartDate | 1930 ⓘ |
| category |
4-8-8-2 locomotives
ⓘ
Southern Pacific Railroad locomotives ⓘ articulated steam locomotives ⓘ cab-forward steam locomotives ⓘ oil-fired steam locomotives ⓘ |
| classPredecessor |
Southern Pacific AC-5
ⓘ
linked to:
Southern Pacific AC-6
|
| classSuccessor | Southern Pacific AC-7 ⓘ |
| configuration | 4-8-8-2 ⓘ |
| country |
United States
ⓘ
linked to:
United States of America
|
| cylinderArrangement | simple articulated ⓘ |
| cylinderCount | 4 ⓘ |
| designer | Southern Pacific Railroad ⓘ |
| disposition | all units scrapped ⓘ |
| driverDiameter | 63 in ⓘ |
| era | early 20th century ⓘ |
| fleetNumbers |
Southern Pacific 4100–4149
ⓘ
linked to:
Southern Pacific Cab Forward locomotive
|
| fuelType | fuel oil ⓘ |
| gauge | 4 ft 8 1⁄2 in (1,435 mm) ⓘ |
| introduced | 1930 ⓘ |
| notableFeature |
articulated frame for sharp curves
ⓘ
cab located at front of locomotive ⓘ designed for long tunnels and snow sheds ⓘ |
| numberInPreservation | 0 ⓘ |
| operator | Southern Pacific Railroad ⓘ |
| powerType | steam ⓘ |
| primaryUse | heavy freight service ⓘ |
| railroad | Southern Pacific Railroad ⓘ |
| railwayCompany | Southern Pacific Railroad ⓘ |
| railwayPreserved | none ⓘ |
| region |
United States
ⓘ
linked to:
United States of America
|
| retired | 1950s ⓘ |
| totalProduced | 50 ⓘ |
| trackGauge | standard gauge ⓘ |
| tractiveEffort | 124300 lbf ⓘ |
| UICClassification | (2′D)D2′ h4 ⓘ |
| usedBy | Southern Pacific Railroad ⓘ |
| usedFor | mountain freight trains ⓘ |
| usedOn | Sierra Nevada routes ⓘ |
| valveGear | Walschaerts ⓘ |
| whyNotable | cab-forward design for long mountain tunnels ⓘ |
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: Southern Pacific AC-6 Description of subject: The Southern Pacific AC-6 was a class of massive articulated cab-forward steam locomotives used by the Southern Pacific Railroad, notable for their distinctive design optimized for long mountain tunnels and heavy freight service.
Referenced by (4)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Southern Pacific AC-6
linked to: Southern Pacific AC-6