i have to make a working model can you tell me any working model with instructions???
A working model of WHAT ? That would help us answer your questionA few simple thoughts would be a Lego or Erector-set kit that would permit you to build a crane or tram or electomagnet-craneYou could also go to a model railroad shop and buy a turntable or cantilever bridge model (around $15-40USD) Good luck !!