Bottom-blowing the glass does nothing for the top opening. ther is a proper procedure for blowing out and testing the glass. Simply opening the bottom cock or the drain cock is not it.
Try cocks are just as dangerous, if not more so, than water glasses. Properly maintained and operated try cocks can give a false water level reading, as was proven in tests done by the ICC in the 1920's. Conversely, properly maintained and operated water glasses will not give a false reading. That is why, shortly after the ICC test results were published, most railroads started adding a second water glass to their locomotive not so equipped.
Some of you devotees might get angry at that, but it was tested, it was proven, and it was retested by other entities and proven time and again. It's why commercial boilers have not had try-cocks for decades. The things are not reliable, period.
Try cocks give a false reading caused by the water rushing to the opening when the cock is opened. The false reading may be an inch or less, but it will be false and it will be higher than the actual water level.
I also think it's instructive that the entire discussion long ago deteriorated into personal attacks on the inspectors rather than a reasoned discussion of the known facts and the results of actual inspections, tests, examinations and measurements. Some of you guys are simply shooting the messenger when the messenger reports something you don't like or don't understand.
It's becoming clear that this traction engine was a junker with a partially rotten boiler (0.010 sheet thickness in some places) and certain boiler appliances that were completely or partially inoperative (safety valve, steam pressure gauge, etc.).
Responsibility for the condition and safe operation of any boiler rests entirely on the owner and/or the operator, not on the state of the state's inspectors.
