For glacier travel you learn to set up 2x, 3x, 5x, and/or 6x pulley systems for rescues. 6x leverage means a 100 lb. pull on the rope yields a 600 lb. pull on the working end (less friction losses, of course).
Materials are very lightweight, because you need to carry them on your back or attached to your harness. One rope, a few loops of lighter ropes to set up prussiks (one-way sliding knots which serve as ratchets), a couple of lightweight pulleys, couple of carabiners, and a few odd slings to set up an anchoring point.
My whole rescue kit, rope aside, weights about a pound. Add a 2000lb test rope and it might weigh another pound, maybe two. There are probably diagrams of such systems all over the web, available in .29 seconds by Google search.
Hope that helps.