A propulsion system used on
Star Trek. Transwarp works by tunneling through
subspace to travel along a strighter path than would be possible in normal
four space. A standard
warp drive can be used in conjunction with a transwarp conduit to acheive even higher velocities.
There seem to be two forms of transwarp conduit, permanent and temporary, permanent conduits are like low end artificial wormholes and don't require a special drive to use (just a way to trigger the opening). Temporary conduits use a Transwarp drive and can be created anywhere, to anywhere and although the length is still partly determined by the realspace distance, it is generaly much shorter. It seems that a ship without a transwarp drive can use a temporary conduit to travel with the ship that is generating the conduit
An interesting idea would be that all conduits are permanent and if you can figure out how to open the correct one, you can travel along the path of any ship which has previously used transwarp, assuming you are at an end point. Of course detecting the opening, and further figuring out how to open it, AND making sure it's the right one, could present problems. A race/ship/whatever that went around exploring old conduits to try and find usefull ones would be quite interesting, especialy since it would present a high risk of jumping into the middle of a bunch of Borg.
In typical Voyager style, it was found that transwarp wasn't good enough, and so they came up with Quantum Slipstream, and them promptly said it was the same thing. This follows the trend of Voyager to not use an old bit of technobabble when a new and incompatable one can be used instead.
I made parts of this up to fill in gaps left by the shows. it is not in any way official and will probably be shown incorrect by future episodes (most likly the bits that I DID get from episodes will be the first to go).
Based on the Voyager Finale, it looks like the permananent conduits are MUCH faster than the temporary ones(at least with regard to
The Borg, the
Voth and other transwarp capable species may be more advanced). Voyager has used temporary transwarp before and managed to shave off months or years in a a day or so of travel while a permanent transwarp conduit managed to get them home in a few minutes.