Tim O'C inquires about the effect of weight on truck rolling test data.
I do not routinely test truck rollability with/without weights, although I do so on occasion. My reason for not doing so is that I use the test data to conveniently guide my choices of wheel sets going forward (not excluding leaving OEM alone!) without having to parse out with testing anew with each install the usual small inherent differences resulting from both variable weighting, but also rollability differences caused by the common variability between nominally-identical trucks. Sometimes the weight improves rollability, occasionally in dramatic fashion; while at other times, the same weight can all but stop a truck dead in its tracks. Most of the time, in real time, it makes no difference.
As to the new Kadee trucks, I did indeed test the Barber S3 with and without weight. The weight (a 1-oz. lead block balanced on the truck bolster) caused the rollability to improve, but ever so slightly- remaining still in the midst of the Acceptable/Good field. This was why it was not mentioned.
Denny S. Anspach MD