I sometimes wonder about the often-heard statements that K28's and 69 were not well liked and didn't do well in the winter. A lot of the 770th ROB and WPYR guys I talked to over the years seemed to think the K28's and the 69 (aka The Gila Monster) did just fine and were pretty good machines. A lot of the documentation from late 1942 to 1944 indicates heavy usage of these locomotives. Of course, it could just come down to the fact that they didn't have much choice but to run the heck out of them in an effort to get tonnage over the mountain.
That's an interesting theory about the 10 and 14 getting there before the Army leased the railroad. I'm away from my research material at the moment, but I seem to remember they got to Skagway in the fall of 1942 after having been requisitioned by the Army, which would lead me to think they were indeed Army engines and would have been lettered USA just like the K28's, the Silverton and C&S 2-8-0's, the 190's, and a few others I'm sure I'm missing. But I also remember they seemed to be preferred passenger power up there, so maybe the remaining WPYR management "claimed" them with the intent of retaining them when the Army turned the line back over? Especially after what seemed to be an incredibly thorough heavy rebuild/customization done by the NP.
Was the Klondike Mines #4 purchased by the WPYR or was it requisitioned by the Army? Of the locomotives that showed up during the war (other than the 190's they kept), I believe she was the only one that survived the war and kept working up there.
There are several mysteries remaining to be solved, that's for sure! Now if someone could just prove the Silverton Northern #34 actually made it to Skagway...and wasn't the former Alaska Railroad #152 (now at the Huckleberry) supposed to have been there too?