I nominate the AT&SF articulated locomotives, with the ‘hinged boilers’ as plug-ugly. I will withold the superlative “Ugliest” for later. I must admit I don’t know anything about the Santa Fe locos, but they just struck me as weird. Maybe they had nice personalities…
My nominee is the JNR 9600-class 2-8-0, as they appeared late in life (air brakes stuck on as afterthoughts…) They had all the grace and beauty of a pit bull:
There were also some (???!!!) steamers used on Spanish mining lines in the early to mid century, with odd machinery arrangements and strange-looking accessories. See Rails to the Setting Sun by Charles Small.
My guess is that this might have started out as a 4-4-0 that’s been on the scrap line for a while and has been cannibalized pretty thoroughly. Note that it’s missing piston rods, main rods, side rods, perhaps the rear axle and wheels of the engine truck, and probably a lot of interior parts.
I have never before said any steam loco is ugloy but your 3322 is an exception. Boy is it ugly to me. No the N&W is downright good looking in comparsion.