Perdonad qué este en ingles, pues lo escribí para un concurso de un foro en ingles y aun no lo traduje.
USS Yorktown, class Yorktown
Launched in 2230s
First Warp 8 capable ship of the Federation. Initially failed to break the Time barrier (warp 7.3) because his warp core not was capable of make enough power to do it. Even which this flaw, this new cruiser was produced in some quantity because was the only ship in star fleet that can match the Klingon D-6 battlecruiser (which a bit changes in the basic design of the ship to carry experimental weapons and better shielding), and build quickly. When the Constitution class begin to be produced, this class was displaced by the Conie. But after it, this class, and in special, the USS Yorktown make history when finally in 223X [6, 7 , 8….] before a refits in the warp core (Eight series Mk Ia warp core), can break for first time the Time barrier and reach Warp 8.
His Main Engineering room and his Warp 8 reactor (Eight Series Mk I , Mk Ia and Mk Ib ) give the patch for future ships Eng. Rooms and Warp cores, like the Constitution class. It uses a horizontal intermix core, more longer that Warp 7 series reactors that are controlled & moderated by Dilithium crystals or Diliithium contaminated Lithium crystals (usually used this last … and usually shorted his name to Lithium).
The Eight series Mark I, Ia and Ib are similar to previous Seven series Mark VI warp cores, that are divided in a low power antimatter-mater reaction section that works which a intermix of matter-antimatter of 5:1 to generate low power but great quantity of electro plasma and a high-power reaction section. The low-power section can generate around 30% of a ship, enough for a starship normal operations and low speed warp fly. The low power section uses eight plasma injector and two dilithium or lithium crystals to moderate and control the matter-antimatter reaction. The high-power section supply around 70% of the ship power, it works hiperheating the electro plasma generated by low power section which a reaction of 1.5:1 intermix ratio. This extra power is used mainly in high speed warp flys, and in yellow and red alerts to give power to shield and weapon systems (some times, this is called “military power”). The high power section uses 6 high power plasma injectors and one dilithium or lithium crystal to control and moderate the reaction.
This configuration of two stages warp core, was very usual in the late 22nd century and first half of 23rd century based over the high efficient Tellarite warp core tech. This configuration of warp core was abandoned in 2270s which the arrive of Eight series Mark III warp cores (in the Constitution refit program) that uses a huge vertical intermix section which a intermix ratio of 2:1 to give all power which less technical complexity and giving more 1000 teradynes per second of max power output (previous Eight series only can give max power outputs between 800 and 950 teradynes)
The plasma injectors are assisted which magnetic constrictors to give more safety in case of any technical problem which the injectors. Plus there two stations to control the warp core and a computer core, this are double redundant (which his twins placed in the opposite side of the room. Like nearly all ships of his time and before of it, his warp core can’t be detached (but can eject the antimatter cargo pods), but in case of a confinement fail in the warp core, this ships can detach his saucer by explosive bolts and using it like a huge lifeboat.
Other things that are exemplary in this engineering room and directly predated later ships, are the panels interface (initially based in the 22nd century optronic tech, and late upgraded to duotronic tech), the placement of the warp field geometry control room, or the use of a sliding bulkhead to isolate the high-power section in case of emergency (a plasma leak, etc…).
The main power manifold, that distribute around 70% of the warp core power are placed directly over the high power section getting the electro plasma directly thanks two big EPS conduits. In addition, like previous ships, the warp plasma balancer are located in side of the main power manifold. The main power manifold use triple redundant high power plasma relays to minimize the problems give by power surges.