Interesting idea. Why would this be better than a set of railway lines down a hill side into a forest pulling up standard goods carriages full of rocks? You g

Interesting idea. Why would this be better than a set of railway lines down a hill side into a forest pulling up standard goods carriages full of rocks? You get a forest (which buffers runaway carriages and does all the other lovely forest things) and energy storage on the hill. All using largely commodity items and you can build it anywhere there's a spare slope.