Within Blue Book
Why Did Blue Book Leave Cheyenne Unidentified?
The 1955 Cheyenne report remained officially unidentified even though investigators blamed distorted locomotive noise and witness expectation.
On this page
- What the hunters reported
- How investigators traced the sound to a train
- Why the official label conflicts with the file
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Introduction
Among Wyoming’s Project Blue Book files, the Cheyenne case from October 1955 is notable not because it remained a compelling mystery, but because it illustrates how an official classification could differ from the investigators’ own explanation. The incident involved hunters who reported an unusual sound and a disputed visual observation near Cheyenne. Although the Air Force ultimately left the case in the “Unidentified” category, the investigative file argued that the strange noise almost certainly came from a distant locomotive whose sound had been distorted by atmospheric conditions and then interpreted as something extraordinary. The tension between the written explanation and the official label has made the case one of the most revealing examples of how Blue Book sometimes handled uncertain reports.[govweird]govweird.comProject Blue Book UFO Sightings in Wyoming (1947 to 1969) · govweird · govweird…
What the hunters reported
The October 1955 incident occurred near Cheyenne while local hunters were outdoors at night. Their attention was first drawn by an unusual sound rather than by a clearly observed object. As they tried to determine its source, they also reported seeing something that they considered unusual enough to notify authorities.
The witnesses did not provide the kind of detailed visual description found in some other Blue Book cases involving pilots or multiple independent observers. Instead, the report combined an ambiguous visual impression with an unexplained noise. That distinction is important because the sound became the central focus of the investigation rather than the appearance of any supposed aircraft.
Within the wider Wyoming record, the case stands apart because it was driven by the witnesses’ interpretation of an unexpected experience rather than by sustained observation of a well-defined aerial object. The available documentation therefore offers much stronger evidence about what investigators thought caused the event than about what, if anything, was actually seen.[govweird]govweird.comProject Blue Book UFO Sightings in Wyoming (1947 to 1969) · govweird · govweird…
How investigators traced the sound to a train
The Air Force investigation concentrated on identifying a conventional source for the mysterious noise. Investigators concluded that the most likely explanation was a locomotive operating on nearby railway lines.
Cheyenne was, and remains, one of the most important railroad centres in the American West. Freight traffic was common, and investigators noted that atmospheric conditions can refract and carry low-frequency sounds over unexpectedly long distances. Under suitable weather conditions, locomotive noise can appear to come from an unexpected direction or seem detached from its true source.
The file also suggested that expectation influenced how the witnesses interpreted the experience. Once the unusual sound attracted attention, any indistinct light or distant visual feature could have been connected mentally with the noise, creating the impression of a single unexplained event rather than two unrelated observations.
This explanation did not require fraud or unreliable witnesses. Instead, it relied on a combination of ordinary environmental conditions and normal human perception—an approach that was typical of many Blue Book field investigations when a straightforward physical cause appeared available.[National Archives]archives.govNational Archives Project BLUE BOOKNational ArchivesProject BLUE BOOK - Unidentified Flying Objects | National Archives…
Why the official label conflicts with the file
The unusual feature of the Cheyenne case is that the paperwork does not point in a single direction.
The investigative narrative argues that distorted locomotive noise, together with witness expectation, provides the most plausible account of what happened. Yet the case was not formally closed as “identified.” Instead, it remained in Blue Book’s official records as “Unidentified.”
That apparent contradiction has attracted attention because it demonstrates that Blue Book’s summary classifications were not always perfect reflections of the underlying investigations. Researchers examining the original files have found several examples where the record card, investigator’s reasoning and final category do not align neatly. In Cheyenne’s case, the written explanation appears considerably more confident than the official label suggests.[govweird]govweird.comProject Blue Book UFO Sightings in Wyoming (1947 to 1969) · govweird · govweird…
The discrepancy may reflect administrative practice rather than a deliberate attempt to preserve a mystery. Blue Book investigators often worked with incomplete evidence, and headquarters occasionally retained a cautious classification even when a probable explanation had been proposed but not conclusively demonstrated. That left some files occupying an awkward middle ground: effectively explained in narrative form but never formally reclassified.
What the case says about Project Blue Book
The October 1955 Cheyenne file is valuable less as evidence for an unexplained aerial phenomenon than as evidence of how Project Blue Book operated.
Several lessons emerge:
- A case could receive a conventional explanation without investigators being able to prove it beyond doubt.
- Witness sincerity was not automatically questioned; investigators instead examined environmental and psychological factors that might have shaped perception.
- Official Blue Book categories should not be treated as the whole story. The supporting investigation may contain conclusions that are more nuanced than the final record card.
- Reading only the headline classification can therefore give a misleading impression of the strength—or weakness—of the evidence.
This makes the Cheyenne incident an important companion to other Wyoming Blue Book files in which the detailed investigation and the final administrative label do not fully agree. Rather than strengthening claims of an unexplained craft, the case highlights the practical difficulties investigators faced when reconstructing brief, poorly documented events from witness testimony alone.[govweird.com]govweird.comProject Blue Book UFO Sightings in Wyoming (1947 to 1969) · govweird · govweird…
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Endnotes
1.
Source: govweird.com
Link:https://www.govweird.com/topics/ufo/project-blue-book/state/wyoming
Source snippet
Project Blue Book UFO Sightings in Wyoming (1947 to 1969) · govweird · govweird...
2.
Source: archives.gov
Title: National Archives Project BLUE BOOK
Link:https://www.archives.gov/research/military/air-force/ufos
Source snippet
National ArchivesProject BLUE BOOK - Unidentified Flying Objects | National Archives...
3.
Source: wyoarchives.wyo.gov
Title: Blue Book
Link:https://wyoarchives.wyo.gov/pdf/BlueBookFinal.pdf
Source snippet
Volume V Phillip J. Roberts, Ed...
4.
Source: archives.gov
Link:https://www.archives.gov/research/catalog/catalog-bulk-downloads/uap-bulk-download
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April 24, 2025 — STILL PICTURES AND PHOTOGRAPHS UAP RELATED RECORDS Level of Description | Title | Link to Metadata | Link to Full Zip...
Published: April 24, 2025
5.
Source: archives.gov
Link:https://www.archives.gov/research/topics/uaps/textual-and-microfilm
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icrofilm | National ArchivesApril 24, 2025 — RECORDS RELATED TO UNIDENTIFIED FLYING OBJECTS (UFOS) AND UNIDENTIFIED ANOMALOUS PHENOMENA (...
Published: April 24, 2025
6.
Source: archives.gov
Link:https://www.archives.gov/news/articles/project-blue-book-50th-anniversary
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December 5, 2019 — PUBLIC INTEREST IN UFOS PERSISTS 50 YEARS AFTER PROJECT BLUE BOOK TERMINATION By Jonathan Marker | National Archives N...
Published: December 5, 2019
7.
Source: archives.gov
Title: Please update your links and bookmarks. C
Link:https://www.archives.gov/foia/ufos.html
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Project BLUE BOOK - Unidentified Flying Objects | National ArchivesAugust 15, 2016 — PROJECT BLUE BOOK - UNIDENTIFIED FLYING OBJECTS THIS...
Published: August 15, 2016
8.
Source: govweird.com
Link:https://www.govweird.com/topics/ufo/project-blue-book/year/1955
9.
Source: govweird.com
Link:https://www.govweird.com/
10.
Source: govweird.com
Title: offutt afb neb october 1953 28956540
Link:https://www.govweird.com/topics/ufo/project-blue-book/offutt-afb-neb-october-1953-28956540
Published: october 1953
11.
Source: govweird.com
Title: lake city tenn november 1955 28964211
Link:https://www.govweird.com/topics/ufo/project-blue-book/lake-city-tenn-november-1955-28964211
Published: november 1955
12.
Source: govweird.com
Title: sonora calif october 1955 28964039
Link:https://www.govweird.com/topics/ufo/project-blue-book/sonora-calif-october-1955-28964039
Published: october 1955
Additional References
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Source: youtube.com
Title: Project Blue Book: Declassified
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Project Blue Book UFO files investigations cases Project Blue Book's 10 Scariest UFO Files: Cases They Couldn't Explain America's Strange...
14.
Source: theblackvault.com
Title: 14 was a massive statistic
Link:https://www.theblackvault.com/documentarchive/project-blue-book-special-report-14-may-5-1955/
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Project Blue Book Special Report #14 – May 5, 1955 - The Black VaultSeptember 17, 2020 — PROJECT BLUE BOOK SPECIAL REPORT #14 – MAY 5, 19...
Published: May 5, 1955
15.
Source: youtube.com
Title: Project Blue Book What the Government Really Found About UFOs Declassified Files
Link:https://www.youtube.com/watch?v=58vD_C2oXnk
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Project Blue Book: Declassified - The True Story of the D.C. UFO Sightings | History...
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Source: youtube.com
Title: The True Story Behind US Government Investigations Into UFOs | Project Blue Book
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17.
Source: youtube.com
Title: Project Blue Book’s 10 Scariest UFO Files: Cases They Couldn’t Explain
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Title: Project Blue Book UFO Archives 9 UNSOLVED Cases
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Source: zenodotusproject.blogspot.com
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Source: commons.wikimedia.org
Title: File:Project Blue Book report 1955 05 11884637 Analysis of reports of UAO
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22.
Source: commons.wikimedia.org
Title: File:Project Blue Book report 1956 08 7070170 Cheyenne Wyoming
Link:https://commons.wikimedia.org/wiki/File%3AProject_Blue_Book_report_-_1956-08-7070170-Cheyenne-Wyoming.pdf