Nodes are the strongest part of the scaffold, ledgers, transoms bracing etc should be no more than 300mm max apart, the closer the stronger the node, node points should also be " run in " around the bay, as they transfer the load through themselves, weak node = weak scaffold. the transoms only count if they are a load bearing fitting..ie. not a lap. the load bearing tube for example on a boarded working lift would be the ledgers ( on 90's ) and not the trannies ( on laps ) therefore in theory although we would call the ledgers, they are actually transoms as they are load bearing with the doubles and the trannies ( laps ) would be the ledgers... Know what I mean ?? lol..