Bruce A. Metcalf
On 6/26/20 4:37 PM, Bud Rindfleisch wrote:
Just curious on your opinions on weighting freight cars to NMRA specs. As an S scaler I've always subscribed to the recommended 6 oz's but our Groups io, has been having on going discussion about not weighting the freight cars and tracking ability on scale flanges and mostly code 100 track. Some say they do not add weight to plastic or resin cars but use metal trucks and metal wheels. I do that anyway but I prefer them slightly heavier than a plastic or resin kit without weight.I think it's important to understand the conditions under which the NMRA established those weight standards. It was an era before RP-25 wheel contours, before needle-point axles, and when car sides were as likely to be cardstock as Zamac. Thus the standards are optimized for very heavy, bad-rolling cars.
I think it's well past time for us (meaning we NMRA members who care enough) to go through the testing again to see if the standards hold up with modern technology. But until we do....
I use the NMRA weights in HO. I have also found that when there are problems, it's not the absolute weight, but combinations of light and heavy cars in one train. That, or putting light cars or just too many cars around too-tight curves.
The NMRA gives us a starting point. It also reminds us that you probably need more than just so much per inch. I know modelers -- and clubs --
that have deliberately used underweight cars with good success. I think the key is to make *all* the cars underweight by about the same amount.
Don't know if that answers your question, but I tried.
/ Bruce /