I have Steam Across America on video and I know that during the filming of the video Cotton Belt 819 received a load of 'bad oil', which resulted in thick, black plumes of smoke. I searched for 'cotton belt 819', 'cotton belt 819 with bad oil', and 'cotton belt 819 with bad fuel' on YouTube, with no luck. If I could have found the video, I could have shown an example of what I was asking about. Also, during the Tennessee Valley Railroad Museum's 2015 Railfest, Southern 4501 developed some problems on the Sunday morning Chattanooga-Cleveland excursions, which resulted in her being taking off and replaced by veterans unit SD60E #6920 for the afternoon excursion. I don't know if there's a connection, but I've heard two different reasons why. Either it was a load of 'bad coal' or that problems with the grates developed during the morning excursion. I also must note that I have a picture of 4501 having the front of the smokebox open with a guy in there with a rake, shoveling out soot from the smokebox.
@flyboy559:
I know that crews often toss some sand into the firebox of oil-burners and the sand goes thru the boiler flues, removing some of that crud. This sounds like a dumb question, but, can you just use more sand to clean the flues or is that not possible to do without making the situation worse? Such as causing a blockage in a flue?