On a school special I made several years ago, with Jerry firing, we left McEwen with a pretty good fire in the 3. Jerry fired steadily to Hwy. 7, about 2.5 miles, where he quit firing to reduce spark emission. At Ballast, one+ miles from Hwy. 7, the safeties lifted. When we got to Sumpter Jerry put in a few sticks to hold the fire while we were waiting. At no time was the water less than 3/4 glass. All of this on a steady 1 to 1-1/2 percent grade. Granted, the wood was good although not perfect but I have always considered this a mark to shoot at.
We won't talk about another trip where we stopped short of the platform at Sumpter and I had to restart on a 1.64 percent grade with 65# of steam.