Why did Union Pacific stopped running steam locomotives on the Northwest District in 1947-48
UP didn’t have enough diesels in 1947-48 to completely dieselize the Northwestern District. See Willard V. Anderson’s excellent article “Extra 1555 West” in the May 1950 Trains magazine. Steam was still very much in evidence in Anderson’s article.
why UP wanted to move on from steam locomotives. in fact why UP hated steam locomotives, they should retire them earlier 1951-2 like, say, Pere Marquette
I am presuming UP’s Northwest District is Oregon/Washington. There were some coal mines east of Seattle on the NP and the Pacific Coast RR, but I am not aware that UP had any coal branches in the area. Other than that, it’s a long way to sources of coal and oil. That’s my guess anyway about sidelining steam.
So there is NO Union Pacific steam locomotives running in the Pacific Northwest after 1947 or 1948 at all.
I have no idea why you would say this, let alone keep repeating it. Don Strack says that the South-Central District (which had bad water) was the dieselization priority, and that’s the district that was dieselized by 1948. The Northwestern District was not fully dieselized until well after 1950 (that being when the rebuilt F3s began to be sent there). I don’t know the historical date the last steam was assigned to a train, but it was much later than 1948.
Where do you come up with the notion that UP (or any railroad) hated steam locomotives? Like most other railroads, UP found that diesels cost less to operate and maintain, so they dieselized at the best reasonable rate. FYI, Pere Marquette was absorbed by C&O in 1947.