Jefferies tube
On Star Fleet vessels, Jefferies tubes are internal maintenance conduits that are used to provide crew access to various ship's systems.
In emergencies, they can also be 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". It wasn't until the 24th century that their official name was firmly established.
- 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.
Horizontal tubes
Horizontal crawlways allow for manual access to various vital parts of a ship or station. Dim lights are located near the floor, and on each side of the tube.
Crewmen usually have to crawl, due to the cramped size. Inside these tubes are removable panels to important system conduits and engineering controls.
Certain horizontal Jefferies tubes on Galaxy-class starships were full-height service corridors tall enough to walk comfortably in. These tubes had ladder-access to other decks.
Vertical tubes
Vertical tubes allowed for manual access to decks both above and below, which are labeled inside. Dim lights are located behind the main ladder, and other lights are found on every deck.
These tubes are equipped with a single one-way ladder for crewmen to climb or descend.
