So if you put together a long (10? 20? more?) cut of those without weights, at what point does stringlining on curves start to become a concern? I should think you could get a fair number together, provided (1) they are free-rolling, (2) your curves are not unreasonably tight; and (3) you don't tack any heavy cars on the end.
Ed
I think the weights are necessary to keep the car on the tracks just through turnouts and small rail height discrepancies, especially with the 28" FVM wheels. I was also concerned that the articulated joints would lift or bounce out of the trucks since it's just gravity holding them down. The printed bodies and trucks only weigh a couple grams. I don't know how much train I could put behind these without stringlining but I guess we may find out one day.
This test felt good, I was expecting problems and didn't really have any.
Turns out those DI weights are 14g each (I would have thought more), which is exactly half the NMRA recommendation for the length of the units. So my target total weight for each unit needs to be like, 16-17g? I can get about 4-5g of tungsten rod and putty into the interior of the spines, and an unweighted 45ft trailer is ~8g, so I may only need to add ~5g more tungsten to the trailers get these to run as nicely as the test. Hopefully the tungsten in the spine will lower the center of gravity enough to balance out the top-heaviness of the trailer.
