I have been searching my memories, which get fuzzier by the year, trying to remember the story I was told about that. As I recall Pops told us that it was his father that did it. I don't recall the date but I think it may have been the 487.
I have my doubts that it was a simple "night crawler" incident caused by a leaky throttle. The engine would have had to be moving at a fairly good clip to plow through a brick wall and push three boilers off their foundations partly through a second wall. My theory is that a hostler was either moving an engine into the stall or repositioning one with a very full boiler, got a slug of water into the throttle, and it took off on him. I presume that the boilers were still being used when it occurred or they would not have bothered repairing the damage to the them.
Mark, do you remember any more about that?