Re: Thank you Sir!

Whenever you look at the operation of railroads or any industry in this country, or any country where capital is king, always remember "bottom line costs" is the driving force behind any business decision. Too often modelers and fans will assume that an operating decision is based on something esoteric like your "wear and tear on equipment." Operating decisions are based on profit and loss. Nothing else.
One classic example is the old argument as to which color was used to letter equipment on the Rio Grande Southern, white or silver (aluminum). The answer is, of course, whatever they had on hand. If they just painted geese then you'd see aluminum. Bottom line. Don't buy paint to meet a "standard" when you have material on hand.
This is not meant to be an indictment of any kind or to infer that there is anything wrong with this system but rather to merely inform that this is the way it is. If we want to understand why something was done, look at profit and loss first.