Why are the N scale Spectrum 4-8-2s SO BAD?

I Swear i have two of these blasted things, an no matter what i can't get them to run for crap.

I do every little trick under the sun i know to try and keep these things from derailing, yet EVERY time i try and use either one it just derails with no hint as to even why its doing it.

EVERY time, without fail they just fall off the tracks, Specifically the Pilot and the front driver set. EVERY time. I have engines far bigger than these things, even one that uses the exact same mechanism, a Bachmann Spectrum J class, it runs like a dream, never derails, even on my 9.5in radius yard tracks, yet for SOME reason i can't get these blasted mountains to be behave worth a dime.

I've checked the Gauging, I've adjusted the base plate since it was causing the front axle to bind and not have full range of motion, I've tinkered with everything i know to do to try and fix these things, and NOTHING works.

And its not like i have tight corners, 12.5in radius and 11.25in Radius, Not HUGE for N Scale, but well in the range of what that engine is made to run on.

Even stupider is that it derails LESS on the 11.25in Radius track. The TIGHTER track!