Being new to working with N scale, I have been looking at a series of tests. The prelude to this activity has been elaborated in these previous posts:
4-11-21 more on the impact of trucks & wheel material and N scale freight cars
4/12/21 truck & wheel set testing begins
For some reason with N scale we are looking at a 7% spread from min to max length. That yields a situation where there is a significant bind & it won’t roll at all or the wheel sets just fall out.
The following chart gives an indication of the possible result combinations by testing five truck pairs from different manufacturers with eight unique groups of wheel sets from various manufactures and materials.
The test consists of letting the car roll down a 4% grade a fixed distance starting from dead stop. The velocity is measured at the end of the fixed distance. Knowing the actual weight of the car, that is enough to determine the energy lost due to the rolling friction.
The blank slots and the ATS slots are clearly a situation that may not likely be workable with the truck wheel set combination. The axle to short(ATS) cases will not hold the wheels in the trucks.
The blank slots have a bind that does not allow the wheel to roll at all. In general, all four axles have this condition. However only one is all that is required for the result. So with further examination some of those could be workable.
For now the the combinations that roll but stop, RBS and the ones that had a recorded velocity are worth some additional work. The question is will some tuning for to the trucks bring these combinations near the 300 plus scale speeds of the fastest(least rolling friction) combinations. Also will the fastest improve as well.
To be sure, so far the best is the MTL trucks & MTL plastic wheels. However, how do these results compare in the statistical family.
Obviously additional studies have been teed up with this discussion. First is to work on the combinations that may show some improvement.
The second is to run a series of cars with the same truck/ wheel set combination. The Atlas metal & the MTL plastic are good candidates. Additionally, the MTL metal option also seems worth while to identify how it does in this test.
The why do we care has to do with the train performance. Rolling friction is something that should be minimized, and there are techniques to accomplish this. The end result will be better train control, more cars pulled and higher speed if you need it.
More work will be done her. When thee data is available it will be included here.
