>I am very pleased with the performance of my NMRA weighted cars.
>No apparent issue with grades either. My S-Helper F3's (A-B) can >haul 40 weighted car trains up Edward Loizeaux's 1.4% grades without >breaking a sweat. >HOWEVER, brass engines pulling weighted cars may be a different >matter all together. >John Gibson >Rocklin, CA Weighting and trackability are interesting issues with many factors. I tend to agree with Dick Karne's opinion that equalized trucks are very important for good trackability. Over and over I have found that derailments are more prone with rigid trucks or so-called sprung trucks wherein the springs are so stiff that the truck is really rigid in spite of having springs. Equalized trucks, whether with softer springs or with a rotating sideframe, do stay planted on the rails better -- especially when backing up. Loosey-goosey is better than up-tight! However, the differences might not be noticeable on a smaller layout with shorter trains and no grades. The typical spare bedroom small flat layout with short 10-car trains will probably not challenge the train/track sufficiently to cause any problems. With a larger layout, 40-car trains, grades, etc., the problems do become magnified since the involved forces become much larger. Also, the radius of curves is an important factor. Getting around 60" radius curves is a heckuva lot easier than a 40" radius curve. For a real challenge, try backing a 40-car freight up a grade and around a curve and keep it all on the rails. Just try it and see what happens. One of the disadvantages of more car weight is that the train is heavier and, in backwards (compression) operation, the cars near the loco will tend to jump the track easier because they are pushing a LOT of weight. With lighter cars, the same length train can be pushed up the hill without derailing. Contrary to popular opinion, lighter cars can stay on the track better in certain circumstances. But, when moving forward (tension), there will probably not be a noticeable difference between heavy and lightweight cars with regard to staying on the track. Unless you have some really sharp curves. Then heavier is better, generally speaking. So what is optimum? Depends on how long of a train you plan to run and whether or not you plan to back it up. Also, if you can design the trackplan so that the long yard lead is downgrade heading into the yard, you will find that pushing long trains downhill is not really so bad after all. Going down, rather than up, does make a big difference. So, if possible, plan to pull trains uphill out of the yard so that you can push trains downhill into the yard when classifying cars. "S"peaking of grades, I had a visit from a comrade S-guy this past Wednesday and he admired John Gibson's 40-car SP Overnight train on loan to the famous NYC. He wished he could have something similar on his layout. He was moaning that his 4%+ grades and sharper curves made it impossible. The main point here is that it is not just car weight that is at work. It is grades, curves, weight, track quality, speed, etc. As a general and perhaps obvious rule, it is best to maximize your curve radius, minimize your grades, have excellent trackwork, equalize your trucks, cross your fingers and experiment. Using the SHS F-units in an A-B-B-A lashup will pull most anything, as John Gibson knows. But, try pulling the same train with a 2-8-0 consolidation and you will see lots of wheel spinning. Thus, some folks prefer lighter car weight to enable one single loco to pull a lengthy train. Nothing wrong with that if that is what you want. Brass vs. plastic is simply a matter of weight (setting "cost" aside for the moment). A heavier train will be shorter than a lighter train -- especially if grades are involved -- if other factors (such as truck rollability) are identical. Simple physics. If you have a flat layout, you might not notice much difference. But with grades and long trains, the differences rapidly become obvious. Is it important? Depends on how long a train you want to run, how steep the grade is, how many brass cars will be in one train at a time, if you crave pusher service, if you avoid it, etc. It is certainly possible you would never notice any difference if your layout operates shorter trains up gradual grades and around large curves. But with steep grades, sharp curves, long trains, there will be some restrictions on what you will be able to do. Perhaps a mattress on the floor just beneath that sharp curve midway up the steep grade. Life without risk isn't much fun! :>) Then there is the matter of uncoupling/coupling on grades. With the new plastic cars and pointed axles, the ease of rolling is much greater than the good olde daze of ACE trucks and/or the typical brass import with large diameter non-pointed axles. Is this good? Or what? Well, it depends. If you want to uncouple/recouple on a 2% grade, you might find the newer free rolling trucks to be a disadvantage. The cars might well roll away to the bottom of the grade many scale smiles away. If the cars don't stay put, how're ya gonna couple to them? So maybe less rollability is actually better in certain circumstances. Thinking it through for your particular circumstances would be a good idea. Thus, a few heavy old fashioned freight cars without ultra rollability scattered throughout a train might be a good way to minimize/eliminate the runaway issue if it becomes a problem. Thus, more weight and more friction can actually be a good thing in certain situations. "S"hoot.......I'm getting carried away here. How about a rule of thumb? Try this on for size: "Take your longest desired train, make sure it's trucks are equalized, back it up the steepest grade, back it around the sharpest curve and add just enough car weight so that everything stays on the rails. Beyond that, there is no need to add more weight. Nothing to be gained and you shorten train length because of the additional weight. The optimum car weight will not be the same for everyone. It depends on what you want to do with your trains and the layout's design." Leastwise that's my rule of thumb and it works for me. And no, this thumb was not found in Wendy's chili in San Jose. I live 10 miles away and the food here is NASG certified. :>) "S"incerely....Ed L. The poll results are in....... To REPLY to the list, use REPLY ALL, to reply to the sender, use REPLY. I do NOT know if this works on all e-mail software, but it works on some of the most common ones. For those of you on DIGEST mode, all REPLY messages go to the list. Change your membership, change your message settings, use our CALENDAR, view shared files or photos, view the list archives, GO TO http://groups.yahoo.com/group/S-Scale/ Yahoo! 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