Anyone knows were the 8 grammes rules come from ? Meaning, that a z-scale freight car should weight 8 grammes in all. And why 8g ? What happens if it weight 5g only? The probability of derailment is higher? Ben
When I was first starting making rolling stock kits, I did a bunch of testing to see how light I could make a car that I could fit in a train of at least 15 cars, and not have it bounce derailed over railjoiners and through turnouts. I tried all kinds of different weights, and settled on 8 grams for a 40', 10 grams for a 50' and 12 grams for a 60' car as about the minimum. The only reason for more weight for the longer car was that they tended to clothesline around turns unless they weight more, and I wanted to make some 60' cars that I could run well. You can run lighter cars, but they tend to bounce on turnouts, so you have to slow down. -Robert
The NEM (European) standard for wagon weight (NEM 302) defines a minimum for Z-scale of 0.12 gram per mm of wagon length measured over buffers, with the option of increasing the weight by up to 30% for wagons with high centre of gravity, long overhangs, or truck mounted couplers. I cannot find an English version, but here is the German: <http://www.miba.de/morop/nem302-d.pdf> This gives the following weights for the wagon lengths mentioned: 40' = 7.2g to 9.4g 50' = 8.6g to 11.2g 60' = 10.2g to 13.3g Robert's weights are about in the middle of these ranges. Jeremy
there is no English version available (for this particular norm). if you go to the source MOROP, you will find: only translated MOROP norms Chris
clothesline or stringline Chris, this is describing what happens when a string of cars going around a curve tensions and is pulled of the tracks, like pulling a string taught (or a clothesline made of string). It can be caused in a number of ways. Cars that are too light don't really tension but rather are simply pulled in a direction different than straight and aren't heavy enough to resist the reactionand are pulled off the track. Sometimes trip pins that are hanging too low get caught on track, switches or track nails and stop dead pulling the train taught and then off the tracks if the loco is pulling hard enough. Randy
this is exactly what was happening with with the string of my hoppers, round a sharp curve, up an incline - it must be because they are too light and/or top heavy (solved when I decreased the gradient back to less steep one) It is comforting to be able to put a name to the problem :angel: thank you Chris
Unfortunately, it's an all too common problem. Fairly easy to remedy though. It usually seems to happen at train shows when running 100 car trains. ;-) We'll have to get some of those heavy tungsten chassis to pull more weighted cars. ;-) Randy
