Re: SVRy #4 stack

Interesting is the fact that the engine has an extended smoke box. Old locomotives with diamond stacks had short smokeboxes with no netting or spark arresting devices inside the smokebox as the spark attesting function was performed by the baffles and netting inside the stack. When spark arresting netting was applied inside the smokebox, it was necessary to extend the length of the smokebox to put all that stuff inside and still have room for the exhaust gases to move somewhat unimpeded. With that in mind, it looks like #4 was a but of trouble maker, and needed both netting in the smokebox and a diamond stack. At some point they removed the diamond stack and resorted to a shot gun stack, but later changed their minds and went back to a diamond stack. Perhaps, the screens were removed when the diamond stack was in use. Having internal netting and a diamond stack would be a serious detriment to steaming...