We use evac tee's. I don't have experance with the tram systems?? I have done a couple of real evac's and they went OK. They both were with just a few people on line, at the end of the day, in a bad storm. We keep the tee's cached at the top of the mountain and then have seperate evac bags with "belay packs" in them. That way we can hand those out to other staff that are not patrollers but trained in chair evac. This seems to work for us. If we have a disabled/special needs/child guest on line we will work our way through the shives and decend the haul line to get the guest securley on the tee. decendign the haul line doesn't happen that often and is usually reserved for the senior patrollers that have more experance and good upper body strentgh.