My apologies for not being able to give credit where credit is due, but a fellow standing next to me suggested that if we had a chute that guided the stone from the side of the flat into the gauge, that would let us unload the stone flats in record time. I added a few suggestions, like the chute should have wheels and ride on the rail head, and should be repositionable from one stake pocket to another.
But on my way home, I reconsidered that. On a day when you're laying ties and rails, you've got a lot of people. They can empty the stone train faster than it can be loaded, with six people to a side. I agree with my anonymous maker friend that it would be faster, but in terms of the system as a whole, it's an efficiency that's not needed.
A better efficiency, having laid track on both the Mill Spur on Saturday and the Main Line on Sunday, would be to get the grade as close to lined as possible. The Mill Spur was pretty darned flat. The Main Line was not, having had recently been culverted and filled with rip-rap. I realize the world is not a perfect place, and that some improvements are already understood even if not always implementable. I'm just voting for a smooth railbed as my favorite.