I know there is a recommended weight for cars, is there a danger for too much? What is “too heavy” ?
The only “danger” I guess would be if you had a train of super-heavy cars you were trying to pull, and your engine stalled and you left it that way for a while (with the wheels not slipping) as that could burn out the motor.
If your cars aren’t evenly weighted - that is some cars weight a lot more than others - that can cause stringlining derailments. Light cars in front, heavy cars in back, and the engine pulls the light cars off the track on a curve.
NMRA Recommended Practice 20.1 has the thinking of a lot of old heads on this subject. It works for me. Most commercial models are light and need extra weight to bring them up to NMRA recommended weight. NMRA states that extra weight simply makes it harder for the locomotive to pull the train. Adding weight to make a car roll down a grade (say a hump yard) doesn’t work 'cause the extra weight increases axle friction as much as it increases the gravity pull on the car. RP 20.1 is on the NMRA website and is worth reading.
NMRA’s recommendation http://nmra.org/standards/sandrp/rp-20_1.html
Too much weight reduces train capacity. If it’s really a lot heavy you get extra wear on the trucks, track, etc.
Some folks have good results with less weight. If you have good track work and wide curves less should work fine.
Enjoy
Paul
Actually, hump yard operation was one driving force behind the research that led to RP20.1. The at-that-time NMRA President did a lot of research on rolling characteristics in order to get consistent hump yard performance. RP20.1 turned out to be the best compromise - neither lighter nor heavier cars would roll as far on a reasonable hump grade.
That was years ago. Some present day cars will roll on a grade that is barely detectable with a spirit level. I know. I own some!
Chuck (Modeling Central Japan in September, 1964 - with flat-switched yards)
Let’s hear it for Reboxx wheels.
Besides the obvious fact that excess weight decreases the amount of cars you can pull the extra weight can cause soft metal sideframes to wear very quickly. The axles eat their way upward into the soft metal unless you install some sort of bushing. I have had this happen on properly weighted cars (to NMRA standards) with BCW and some other brands of cars. Roger Huber