Hi Earl,
I think that you theory has a lot of merit, as I have seen the blizzard of loose scale that can occur when water treatment is added to a scaled up boiler for the first time. When the old Heber Creeper first put the ex-SP #1744 in service in the fall of 1980, exactly the same scenario happened. Fortunately, we were only running weekends, so every Monday, I would drain the boiler, and take out the mudring corner plugs to find the mudring packed solid with scale. It was like cutting a hole in the bottom of a bag of Doritos. It would take me two or three hours to clear the mudring just to where I could see the next washout plug hole. Some pieces of scale had to be broken up inside the mudring, as they were too big to fit through the washout plug holes.
Friday, I would fire up the engine, it would run for two days, and on Monday, I would start the whole process over again, with the mudring packed solid again. This went on for about two months. Had the engine been left to run for an entire month, there would have been serious consequences.
The idea of running with a higher concentration of solids and treatment in the boilers that you have mentioned, may have been a case where the CMO was trying to follow the “Porta” method of boiler treatment. This seems to be the highest tech method of treating locomotive boilers, and I don’t pretend to understand it, but the goal seems to be to get the water in the boiler “thickened up” to about the color and consistency of a chocolate milkshake. I believe that in this state, all of the hard scale is dissolved into the water, and none sticks to the boiler itself. It requires very close monitoring and treatment of the boiler water chemistry to maintain the right consistency, and also requires that the boiler be kept continuously under steam, as well as drained and washed hot to avoid having this glop set up solid. It sounds like it cannot work if anyone involved doesn’t follow ever requirement to the letter, but where it does work, the results are supposed to be wonderful. What you do with a boiler that was inadvertently let cool off would be a very good question.
