I own one of the early PS-1 Railking Allegheny's.... As other's posted it's a real nice model. I don't own the K Line, but it's noticeably smaller... don't know why they chose to make it 1/64 scale... I upgraded my RK Allegheny to RS year's ago with Digital Dynamics, then as GRJ suggested, I added real coal in the tender. also did mild weathering, added piano wire hand rails up front, shortened the distance between the tender and the locomotive... there's a picture of it below...
What I like most about this loco, is that both sets of drivers pivot which is why it can run on tight curves and really doesn't have a huge overhang problem compared to the articulates that have the rear set of drivers fixed to the boiler... the photo below shows the articulated going through an 072 curve from my layout back in Maine 10 years ago. This engine will smoke up your train room in a few laps.
