This was one of the things I learned from my neighbor next door, sand! I was up at the Skunk train working and came back home going next door to tell Scotty about this 1932 something (forget the name) engine that was there and mentioned the sand hoppers out front and he explained it all to me. They were used a lot of course where he was working in the snow of the Sierras.
It's weird, I am using the wrong terminology or something but I can't find a photo of one. This engine had big containers with a funnel bottom on them mounted one sides of the front for sand, but I'll be damned if I can find a photo.