what fuel does these steam locos run on right now, coal or furnace oil ? got to be furnace oil in my opinion.
Nope, still running on good old sulphur-rich steam coal!
Actually, given the plentiful supply of good cheap coal back in the steam days, and the then-need to import fuel oil (no North Sea oil, then), oil burners never really took off in the UK. Some utility mixed-traffic locomotives were converted to oil immediately post-WW2 - they fired ok, but the economics soon ensured a return to coal.