This is an educated guess , since I wasn't there at the time , but the pull out of the west end of devils gate is a hard one and it looks like 12 is priming a bit and that will make even new packing drool and spit. That is also a great deal of steam to be rod blow by and if she is priming a bit they might be the cylinder drains.
in the sunshine pictures the steam blow by is markedly different as is the stack colour so I really don't think 12 is blowing all that badly.
Kevin WIlcomb
Kentucky Railway Museum
152 - Steam Crew