Creating ski gondolas/tramway with Duplos
What I have done so far: used a ribbon like suggested, but more of a clothes ribbon. It works well - the fabric fits in the spot behind the wheels and friction is usually enough to prevent it falling back. I have yet to add the winch (not sure it will be  long enough but will see when I get it next weekend). I used a simple stack of squares to anchor it - on the bottom needed a bit more support for some reason but nothing fancy. 

(The buildings were child made, by the way :)