Kadee trucks and wheelsets have been a hobby standard since ... Central Valley left the trucks business (and if you don't remember CV trucks, you aren't Old). These are great looking trucks, but the split bolster and fiddly wedge you have to put in just the right spot on the overlong mounting screw makes it nearly impossible for me to install these trucks on a model. This is the self-centering feature that's supposed to make the trucks line up with the carbody when you pick them up (and presumably, put the car down on the track. Frankly, this isn't worth the trouble to me. (See my review of the Rix rerailer.) I'll continue to use Kadee's non-self-centering trucks with pleasure. Unfortunately, this means I'll have to find a different vendor for my lighted caboose, as they have dropped electrical pickup trucks from their conventional line.