Operations division
The operations division was the corps of officers and crewmen within Starfleet who specialized primarily in Security or Engineering. ()

Duties 
Members of the operations division may specialize in services and military functions on starbases, aboard starships, and at Starfleet Command as staff officers. 

Operations officers included engineers, security and tactical, and some service specializations such as communications. Operations division personnel also filled administrative posts as yeomen, personnel officers, and portmasters. By the 24th century, this division had new postings established on ships, such as operations officers (or chief of operations).

Uniforms 
The operations division, command division, and sciences division were usually denoted by Starfleet uniform insignia, most often color-coded.

Officers who belonged to the operations division sometimes wore the division color of another department than that which they specialized in. For example, if an operations officer were to become a department head, he or she might have worn the colors of the command division, or an officer with dual specialties in sciences and operations might have worn the sciences colors.

In the United Earth's Starfleet of the 2140s and 2150s, line officers of ops division wore red division stripes on their uniforms.

The red color had been replaced by the uniforms of the 2250s and early 2260s, as beige (or gold) uniforms and work gear were worn by ops division personnel, except security, who wore blue.

Red was again the color of the ops division throughout the later 2260s, worn by line officers and flag officers of this division. () During this time, though, some operations officers continued to wear beige (or gold).

By the 2270s, new uniforms showed different division colors, the operations division was signified by two differing colors, with red backing the Starfleet badge, and also on uniform bands and epaulets, for engineering and maintenance staff. Security and services crew wore gray badge backings and bands.

The operations division was changed again with the 2280s uniforms, with gray representing both security and services, but also sciences. Engineering and maintenance wore gold colors, which also represent some conn divisions like pilots and navigators. The insignia used gave the officer the option of wearing command division white uniform insignia, with another department color like operations' banded across, or the opposite, with department color insignia with command white banded across.

For the uniforms used from 2350s onward,  had become the operations division color, and this continued through several Starfleet uniform styles, including the most recent style, and even several styles observed in alternate futures. (, et al.)

Gallery

Operations division officers

Appendices

Background information 
Following the beige uniforms of the two pilots, red was regularly worn by the security, engineering, maintenance, yeomen, communications, and staff officers during . Communications Officer Uhura normally wore ops red (she wore command gold in a few early episodes) as did Chief Engineer Scott and Yeoman Rand.

For , costume designer Robert Fletcher dressed all officers in neutral colors, with departments identified by a colored circle set behind the Starfleet logo.  Fletcher divided Operations into multiple sections, with some roles such as helm, navigation, and communications marked by the color yellow and engineers and maintenance workers identified by a red circle.  For  uniforms, Fletcher again shuffled some departments around, moving navigation and communications to the Science department, while engineer Scotty and helmsman Sulu wore the burnt ochre of Operations.

The purpose of the colors was only obvious through inference, but in , red was established in dialogue as the "old" style ops color (and gold as the "new" ops color). The decision to switch the meaning of the colors between the TOS and  uniform styles was made in pre-production of .

Most often, in the Federation Starfleet, all captains and admirals wore command division colors; however, there were exceptions which prove that this was not a requirement. In TOS, two commodores,  and Stocker, wore red operations division uniforms and Captain Krasnovsky wore sciences division blue. In the movie era, Scotty switched back and forth from command white to engineering gold after receiving his captain's bars. In TNG-era productions,  had an admiral named Toddman wearing operations division gold, despite every other Starfleet captain and admiral ever seen in this era wearing command colors.

Apocrypha 

In the comic series Crew, engineering officers are depicted as wearing a red uniform, with a red collar, alongside the beige uniforms as depicted in "The Cage" and "Where No Man Has Gone Before". In particular, these uniforms are depicted as only being worn in engineering, rather than elsewhere on the , suggesting that since the engineering section of the Enterprise was never depicted during this era of TOS, such uniforms could have actually existed side-by-side with the beige operations uniforms, thereby continuing the red division color established in .

In Star Trek Online, the operations division consists of mostly just engineering, as security was moved merged with the command division into the new tactical division in 2409.

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