Some early MPC rolling stock had Timken trucks with the fast angle wheels. I like to pick those up when I see them.
Like CW, I've been interested in the early MPC rolling stock with the Timken trucks and fast angle wheels and have collected them when I saw them at the hobby shop, at meets, or for sale online. Those trucks were a carryover from the postwar period, albeit modified to accommodate the needlepoint axles and the "thumbtack" style plunger (although the early ones used a thin rectangular metallic strip glued (badly) in place as opposed to actual friction-fit thumbtacks). They also changed from the standard plastic used during the postwar era to the engineering, aka "Delrin"-type plastic since it works nicely with the needlepoint axle ends to reduce friction. For some reason MPC also filled in the simulated cavities in the truck side frames, leaving essentially an "outline" of where the cavities used to be. I can only speculate it was done to reinforce the side frames since the engineering plastic is more pliable than traditional plastic.
The modifications to the trucks did result in the overall details being not quite as crisp as postwar; perhaps it was due to impurities in the engineering plastic, compatibility issues with the plastic and the molds, the injection process itself, or a combination therein. It also seemed to result in an opaque residue that tends to show up on the surface of the trucks, although I have noticed it's not present on all of those early trucks. The residue can be wiped off but eventually it tends to show up again over time on the affected trucks.
I wish they fixed those issues with the Timken trucks instead of replacing them with those bizarre and completely obscure Symington-Wayne trucks that became the standard up until LTI changed it to more appropriate-looking 100 ton roller bearing trucks.