Before the #12 traveled from Independence, CA to Durango, I happened by its home on the south side of the Eastern California Museum's land. There was a steam-up to make sure the locomotive was ready for a public event the next week.
I was there from almost the start of the fire to the time the #!2 was put back into the storage building. In time the blower was turned off and the pressure continued to rise. The air pump charged the system. Then the locomotive was run to the other end of the track and stopped. The air pump cycled on to recharge the air system. When it stopped pumping the engine was brought back to the front of the building. One stop, and again the pump came on. This cycle of pump-up, run the engine and stop, pump-up again, return the engine to the front of the building was repeated several times.
From my experience, the pump was working too much for making simple stops without a train. I would have expected that several stops with the independent brake should be make before the pump would be required to cycle on. I called and mentioned this to a friend who had been to the steam-up at Laws and has experience with air brakes. He too expressed concern and noted the locomotive was acting this way at Laws.
Our thoughts were that something was not quite right within the air brakes system. I hope that this gets looked into and put right.
Brian Norden