Being new to this hobby, I recently discovered the NMRA RP-20.1 relative to optimum weight of cars based on their scale and length. Much to my surprise when I weighed the cars that I have (hoppers, tankers, boxes, flats, cabooses, etc) I found that all of them are considerably below their optimum weight. I added weight to some of them and discovered that they do truly ride more stable through turnouts, curves and slight imperfections in my layout. My question is this; If weight is important to the smooth running of rolling stock, why don’t the manufacturers produce equipment that complies with the NMRA recommend practice?
Some do but you will pay a premium for the convienience. For me I enjoy getting the cheap ,$1 per car, stuff and making it look and ride like the $20 car. It’s all about what you want to get out of the Hobby and what you want to put into it.