I'm a bit late to the party on this one, sorry. But I'll try to address some things. Yes, converting the Pacifics to Hudsons would've made more sense, but keep in mind that Wabash's fleet of J-1 and J-2 Pacifics were not only ancient and wearing out, but they were also pretty much spoken for during the time a fellow named A.T. "Tony" Scherer proposed the conversion, which incidentally was around 1938, I discovered...much earlier than what was originally thought, because the first P-1 Hudson wasn't brought on-line until fall 1943. The Pacifics were seeing heavy wartime use, and simply couldn't be spared. However, Wabash owned a fleet of 5 Schenectady-built K-5 Mikes which were just sitting there, gathering rust (Wabash did not like the K-5 3-cylinder locomotives). So Wabash pulled ALL their K-5's into the shops and converted them to Hudsons...Nos. 700-704 (inclusive). In fact, due to demand, two more Hudsons needed to be built. Problem: no more 2600's. Solution: grab two broken-down 2700-series K-4 Mikes, Nos. 2743 and 2744, from the dead line and convert them...in fact, No. 2744 was just sitting at Moberly Yard because its guide yoke, power reverser and 1 main rod were all broken. That's okay, the Hudsons came out of Wabash Shops with spiffy polished rods anyway!
The Monticello Ry. Museum in Illinois owns a whistle from Wabash P-1 No. 702. I picked up the steam whistle from the original owner and it was subsequently conveyed to the MRM (they also have one of the flags from the wind wing of No. 706, as well as the front # plate). The whistle's original owner hooked it up to a HUGE air compressor and let it rip. It drained the air compressor within 5-10 seconds and boy was it LOUD, with a steamboat sound. If anyone wants to hear the audio, give me a shout and I'll email it to you. MRM would like to have the whistle rebuilt, as it was "broken" when the original owner requested it from the Wabash when No. 702 was going to scrap (the owner believed the RR simply torched it off its pipe and dropped it down to the ground). I believe once the whistle is fixed, the museum will mount the whistle to their steam locomotive No. 401, so we can hear that deep steamboat sound under steam, as God and the Wabash intended!
I believe NKP No. 765 had a Wabash steamboat whistle attached to it a few years back, when it traversed Wabash lines to St. Louis on an employee special. The whistle wasn't from a Hudson (a K-4 Mikado in the 2700-series, IIRC), but it was a steamboat sound. There are videos galore on YouTube if you're interested.
Oh, and BTW the Wabash tried to interest folks in displaying the Hudsons, in parks and whatnot, but nobody wanted to take the plunge and accept one. Not even Decatur wanted one. Shame. Can you imagine seeing something like this in 2019?
This is all inside-baseball stuff, so my apologies for being so long winded. I just love these locomotives!!
James Holzmeier
Wabash Railroad Historical Society