An orbital tether was a cable that connected a planet's surface to a space station in orbit. A mag-lev carriage was a common vehicle used for moving along the tether.
Neelix spent two years working on one-tenth scale prototype models of orbital tethers on Rinax.
A Nezu colony planet in the Delta Quadrant had an orbital tether over three hundred kilometers long. Moving from the ground all the way to the station took twelve hours. When the planet came under bombardment by Etanian asteroids in 2373, Tuvok, Neelix, and several Nezu escaped the surface using the tether, rising above the interference in the ionosphere so that USS Voyager could rescue them. (VOY: "Rise")
An orbital tether was located on Koralis III, in the Koralis system, but it had been abandoned by 2375. (DS9: "Chimera")