You could combine these ideas, though, and have only a few cars that pull weights up/down the hill, with a crane to load it off. I'm not sure but it could probably allow for a far greater total storage and kWh/$.
Now you've got more moving parts though. You have both trains and cranes involved. I think it's probably simpler and cheaper just to have the one big crane than to do a mixed mode system.
I guess the only advantage the train approach has is if you can get a lot more height out of it -- imagine an elevation difference of 1 km from top to bottom, way more than you could get with a crane. This still uses a lot more land though and needs a lot more rail; just having several crane installations might still be simpler and use less land.
I guess the only advantage the train approach has is if you can get a lot more height out of it -- imagine an elevation difference of 1 km from top to bottom, way more than you could get with a crane. This still uses a lot more land though and needs a lot more rail; just having several crane installations might still be simpler and use less land.