UP 4000's easier to fire than 3900's?

Why would "one think" that?

Probably because the 4000s were coal-fired, and the 3900's were oil fired?

No, the 3900s were coal fired also. Some of the Challengers assigned to passenger service to Portland, OR and Los Angeles were converted to oil firing. However, 3985 was not converted to oil burning until 1989/1990, in order to attend the tenth anniversary of the California State Railroad Museum in May 1991.

I do believe Mr. A. Water

I don't know who you are referring to.

has said the 3985 was not as easy to fire as the 844, but as the 844 is oil as well, maybe he can elaborate a bit more on his question...

Yes, the 3985 was certainly NOT as easy to fire as 844, even though both are now oil burners. The 3985 has a so much larger firebox, which requires that the Fireman MUST constantly be planning ahead, since it reacts quite a bit slower than 844.

Now concerning the 400 class locomotives, although I obviously have never fired one, I did LOTS of research by talking to the older UP Enginemen about the firing characteristics of the 4000s vs. the 3900s. To a man, they all stated that the 4000s where much more "forgiving" than the 3900s, even though both were coal burners. Once the UP blanked off a small portion of the grate area in the 4000s, the became MUCH better steamers and thus easier to fire. Although 3985 was easier to fire when she was still a coal burner, the conversion to oil and subsequent development/improvement of PROPER air intake, she still would humble the Fireman in short order if you didn't pay attention ALL THE TIME.  

220 sq. ft. larger firebox?

220 Sq. Ft. of grate difference????????  Maybe 22 Sq. Ft.

Maybe not. These spec charts show info on 4014 and 3985:

I'd be willing to look at other info if available.

Mark

That would be total firebox heating surface, not grate area...

DV