same thing happened to me when i first build my drop in. what it did.
get some carpet, any carpet, i have 4 pieces cut from excess carpeting stuff rugs whatever, it makes a total of like 4x8 feet. put it behind the rail. done. i wet it a little, if you wet it a lot its really annoying when you fall, just get it moist (gigity) and you slide pretty well, not fast, just enough to keep you balanced easily when you land.