I presume that most modern day depots have sand for the locos delivered by road? If it were rail delivered today, what would bring it in? A VGA with 25KG bagged sand sound plausible, I am guessing that modern depots use allot less Sand than in years gone by as today's computer controlled locos don't slip, as much!
Are there any of the old sand/boiler houses still in use for storing the sand and keeping it dry or is there some sort of modern alternative, non-moisture absorbing sand!!!!!