On Starfleet vessels, Jefferies tubes are internal maintenance conduits that are used to provide crew access to various ship's systems. In emergencies, they are also used for moving around the ship if turbolifts are not functional. Doors within the Jefferies tubes can be sealed for safety or security reasons. It should be noted that on all ship displays of internal structure Jefferies tubes are not displayed, and in some cases show no sign where they could actually fit within the ship. During the 22nd and 23rd century, Jefferies tubes were usually referred to as access tubes, access tunnels, or service chutes. Not until the 24th century was their official name firmly established, though some officers referred to them as "service crawl-ways." (TNG: "Disaster")
22nd century Edit
During the 22nd century, starships were outfitted with long and small service tunnels what would later be known as Jefferies tubes. These were hard, cold, cramped, and poorly lit. Tunnels on some ships joined at a variable gravity "sweet spot." (ENT: "Broken Bow")
Vertical tubes Edit
NX-class ships had vertical tubes to help their crew manually reach decks above them or below them. These tubes were circular from one end to the other. Each tube was equipped with a single one-way ladder for crewmen to climb or descend. The ladders had dim lights behind them so the crew could see where to step. (ENT: "The Crossing", "Regeneration")
Horizontal tubes Edit
The horizontal tunnels were not very different from the vertical ones. They were also circular and narrow. Crewmen had to bend their knees and crouch down at a bent posture while walking inside these specific tubes. A majority of the tube's space was filled with long and thick engineering pipes that went from one end to the other. These tubes were lit from the floor so a person could follow a path. (ENT: "Acquisition", "Vanishing Point", et al.)
23rd century Edit
In the 23rd century, Jefferies tubes were still round and small, but they were better lit by that time and no longer simply a means to get around. They served many different functions and purposes. It was not uncommon to find many technicians and engineers tinkering inside them.
Diagonal tubes Edit
Many diagonal tubes were scattered all throughout starships. These tubes were always densely connected with important system controls, relays, various conduits and vital engineering circuits. Some of these tubes led to crawl-way junctions, while some even continued on inside a nacelle pylon to one of the ship's actual warp nacelles. At the entrance of each tube were two red bars so a crewman could pull him or herself inside. A soft, yet strong light was always emitted from the top and filled the entire tube. Certain tubes had multiple functions, while others had single functions like the tubes which were only designated engineering circuit bays. Each diagonal tube was equipped with stairs for crewmen to walk up or down. (TOS: "Charlie X", "The Doomsday Machine", "Journey to Babel"; ENT: "In a Mirror, Darkly, Part II")
Vertical tubes Edit
The vertical tubes on a starship, also known as gangways, allowed manual access to decks both above and below. These particular tubes were easily accessible in the open hallway alcoves located on every deck. On the walls of these tubes there was a reflective material that perfectly illuminated the entire tunnel. The tubes were equipped with a single "three-way ladder" to allow more than one crewman to climb or descend. (TOS: "Amok Time", "The Doomsday Machine", "The Way to Eden")
Horizontal tubes Edit
The horizontal crawl-ways on starships allowed manual access to various parts of a starship. These tubes were also densely connected with important system controls and vital engineering circuits. Some of these tubes even led to the matter-antimatter reaction chamber. Every few feet, a bright light could be found shining down. Crewmen usually had to crawl while traveling in some of them due to the cramped size. Other horizontal tubes were still cramped, but crewmen could still walk freely up straight in posture. This was especially true late in the 23rd century. Late in the 23rd century, the horizontal tubes were extremely well lit with lights coming from both above and below. (TOS: "That Which Survives"; Star Trek V: The Final Frontier)
Tube junctions Edit
On a starship, the Jefferies tubes had junction service crawl-ways. They served as interconnected points linking all the different tubes. On Constitution-class vessels, these junctions also gave access to critical starship systems like plasma flow regulators and warp and power relays. (ENT: "In a Mirror, Darkly, Part II")
24th century Edit
During the 24th century, Jefferies tubes became more simple, less intricate, and not as thoroughly filled with vital systems.
Vertical tubes Edit
The vertical tubes on starships allowed manual access to decks both above and below, which were labeled inside these particular tubes. Dim lights were located behind the main ladder and other lights were found on every deck. These tubes were equipped with a single one-way ladder for crewmen to climb or descend.
Horizontal tubes Edit
The horizontal crawlways on starships allowed manual access to various vital parts of a ship or station. Dim lights were located near the floor and on each side of the tube. Crewmen usually had to crawl while traveling in them due to the cramped size. Inside these tubes were removable panels to important system conduits and engineering controls.
In 2374, The Doctor sent the EMH Mark II to Jefferies tube 17 aboard the USS Prometheus to release a neurozine gas. The EMH Mark II never accessed a Jefferies tube and The Doctor told him that traditionally such a Jefferies tube is accessed head first. (VOY: "Message in a Bottle")
Tube junctions Edit
On 24th century starships, all Jefferies tubes had junction service rooms. They served as interconnected points linking all the different tubes. Every room had exposed conduits on the walls, sometimes with panels to access various power conduits or relays.
Alien variant Edit
- TAS: "The Practical Joker"
- "Learning Curve"
- "Fair Trade"
- "Before and After"
- "Worst Case Scenario"
- "The Gift"
- "Scientific Method"
- "Year of Hell"
- "Waking Moments"
- "The Killing Game, Part II"
- "Course: Oblivion"
- "Someone to Watch Over Me"
- "The Voyager Conspiracy"
- "Blink of an Eye"
- "The Haunting of Deck Twelve"
- "Renaissance Man"
- Star Trek: First Contact
Background information Edit
The Jefferies tubes were probably named in honor of the 22nd century Starfleet engineer W.M. Jefferies. This character was named after Matt Jefferies, the designer of the original USS Enterprise and the Art Director of Star Trek: The Original Series. (Star Trek Encyclopedia (4th ed., vol. 1, p. 386))
The name was originally an in-joke, already in use during the production of the Original Series, but only came to be canonically mentioned on a number of occasions in the later Star Trek: The Next Generation television series, the first time in that show's third season episode, "The Hunted". Jefferies himself had indicated: "Somebody hung the name Jefferies Tube on it. It wasn't me, but the name stuck and I used it in some of my sketches!" (Star Trek: The Original Series Sketchbook, p. 72; Encyclopedia (4th ed., vol. 1, p. 386)) The first recorded use of the nomenclature was the "SHOT – JEFFERIES TUBE" script reference in the draft of 14 September 1967 of "Journey to Babel" (scene 36, p. 21, where the body of Gav was stashed), though it was not heard in the episode. Set Designer John Jefferies, the younger brother to Matt and who, with his team, had to build his brother's design, recalled the construction of the Original Series Jefferies tube, "It was the only part of that set that was moved on [note: meaning it was a mobile set, mounted on rollers], that was on an incline, and it was made out of a Sona Tube that we cut and expanded a little bit. Sona Tubes were large cardboard tubes that could be purchased. They were used for forming concrete and we would buy these in either eight- or ten-foot lengths and they came in many varying diameters. They ran about a half an inch thick and they were wrapped cardboard. Well, we found these marvelous for pieces of set and curved walls, because they were quick." (TOS Season 2 DVD-special feature, "Designing the Final Frontier")
The access tubes have changed appearance many times in the past forty years, while still maintaining their basic function for both the series and films. The tubes were commonly used as a last minute deus ex machina, whether it was a relay circuit inside that needed to be repaired, or a straightforward means of physical escape.
The most unusual variation of the Jefferies tube was a vertical tube shown in the original Star Trek series. This access tube had a "three-way" ladder that allowed three people to climb simultaneously. This was no doubt convenient during red alert when crewmen needed to get to battle stations quickly. Unfortunately, this concept was never expanded upon, so we never saw a four, or even a six sided hexagon-shaped ladder. Instead, the Jefferies tubes ladders in the 24th century were only capable of supporting one individual.
An in-joke reportedly appearing in the Jefferies tube sets on the original Star Trek series (although written so small as to be invisible to the audience) are labels on the pipes marked "GNDN." This stands for "Goes Nowhere, Does Nothing." The marking also appeared on various sets for the Star Trek films.
Traditionally, Jefferies tubes were cramped crawling spaces, but in the last movie set in the prime universe, Star Trek Nemesis, a particular spacious one was featured, as Star trek archivist Penny Juday has explained in 2002, "The Jefferies tube is used even today. The last feature is an example, where she took the Jefferies tube and made it really big. That's where you see the Viceroy and you see Commander Riker fighting together, is inside a larger version of the Jefferies tube. So, Herman Zimmerman has made sure that the name sticks, and he has always idolized Matt and his work. And he has always tried to incorporate Matt's work and designs and to make sure that the theme is carried on into the new TV series and all of the features. Almost all the time - not in every episode of course - but when we need a crawl space, that's exactly what we use; it's always called a Jefferies tube." (TOS Season 2 DVD-special feature, "Designing the Final Frontier") The canonization of the term "Jefferies tube," however, fell to Zimmerman's successor, Richard James, to implement in the aforementioned episode "The Hunted."