How much ballast is to much!

If they haven't tamped it yet, or if it will settle more, then it is probably the right amount! ;)

On some of the tracks near my old house, the ballast came right up to the railhead between the tracks and outside!

Andrew
 
I think it just depends on what the track is serving. If that track is serving a gravel pit then it is good becase of all the overflow from the hoppers and trucks driving around. Also if it is a coal mine (well it would pretty much have to be black), lumber yard or any other major industry were cars and trucks drive over them on a regular basis.