So I did the math. To store just 1 MWH of energy using a weight would require 8 thousand tons.
Check my math:
1 MWH = 1MJ x 3600s = 3.6 x 10^9J.
Energy = mass x gravity accel x height. mass = energy / (gravity x height)
mass = 3.6 * 10^9J / (9.81N/kg x 50m) = 7339450 kg = 8090 ton.