It was my understanding that 493 was being restored and converted for oil burning for use in times of high fire danger, and they would use the the coal-burners at other times.
They are also purchasing 2 new diesel loco's for use during times if high fire danger.
I'd like to see another k-37 restored and used, but I think for operations during lower fire danger they have all the power they need.
I don't know how much the diesels will be able to pull, and many riders like myself would much rather ride behind a steam locomotive than a diesel, and with the 493 and 2 diesels they might be limited to 2 trains a day during high fire danger. They might like to have another oil burning steamer they can use, but as to if they will convert a k-36 to oil burning during the next scheduled overhaul or restore another k-37, only the D&S can say. We'll just have to wait and see.
I would not be surprised if over the next 10-15 years if they convert all their k-36's to oil burning if the 493 works out for them.