Close to where I live was a rare Footscray tram. It lay derelict out the back of a farmer's house when I looked at it but was still capable of being repaired. As I was leaving, the farmer's wife said "Of course there is the other one". Several weeks later we watched a giant mobile crane lift another Footscray tram out of a clearing in the bush where it had been lying for many years. This one was in good condition and complete.
To the west of Melbourne is the small coastal city of Warnambool. This also jumped on the wagon of tram fever, but opted for cable cars. Eventually, reality caught up to the economics of running a civic tram system and it too went the way of the other country systems. But they have restored a cable car and the history of the cable car operation is a tourist attraction.
So why not model a garden railway cable car system. There is an excellent 1:24 model kit of a San Francisco cable car produced by one of the prolific Italian model sailing ship manufacturers. I would imagine that there would be a base for the track and between that there would be a slot that would allow the "Grip" to be connected and pulled along by a cord stretched just below the slot. A powered winch would haul the cord down the slot. This in turn would pull along the cable car. On reaching its objective cable car returns when another winch hauls it back. Going around corners would require large diameter wheels with the rubber inserts removed leaving large flanges to retain the cord in position. Ideally there should be a continuous circle of cord.
Just a thought.
The other photos show more clearly how my overhead is placed
The derelict tram was burnt several weeks ago.