City of St Louis (NW Modeling List)

[NW Modeling List]

Many UP Challengers were modified to burn oil (including the still-operable 3985) without any major problems.  This would probably qualify as "better fuel" if not better coal.  I don't know if this affected their output or not.  However, the Big Boys didn't like the change in diet on an experimental basis and were not converted to oil-burners.  There appears to be more involved than removing grates and installing an atomizer.  I also suspect that just loading the tender with 14,000 BTU coal without looking into other modifications (drafting being one) isn't the answer either.  UP's on-line coal sources were pretty low quality, somewhere around 10,000 BTU/lb IIRC.

FWIW, UP 844 was also converted to burn oil with not problems mention that I know of.

Dave Stephenson.