I recently acquired 2 PRR K4s' which are 2 rail versions. A previous owner had added DCC to one engine, along with better separate details more closely exacting a late K4s. After removing a seized, fan driven smoke unit ( also owner upgrade ) the loco runs super smoothly. Having no on/off switch for smoke the guy I bought it from complained the loco set up an awful electrical draw. Yeah, no kidding! It will eventually end up being modified for 3 rail but for now remains a shelf dweller.
The other K is unmolested and a curious mix of period incorrectness. Late pilot with a striped tender over a completely black paint job. There are definitely better representations of K's these days but for under $250 for a good running pair, these are just fine, thank you.
Bruce