We all are familiar with the NMRA’s Recommended Practice for the weight of rolling stock . I seem to remember these were offered as a balance between keeping cars on the rails (heavier cars) and letting model locomotives still have a chance to pull a string cars up a reasonable grade with their less-than prototype rail adhesion (lighter cars).
Car weights should be consistent from car to car (with length factored in). Thus, whatever maximum car weight is selected for a layout would need to be consistent throughout all the cars in a fleet. You don’t want some heavy cars and some light cars in a string being backed around a curve.
Also, having too-heavy a maximum car weight would make it difficult to add enough weight to some cars with not enough places to hide the weight (like gons, flats, etc).
Therefore, if a layout has a maximum grade of 0%, and if the heavier a car is, the better it will stay on the rails, then what is the practical maximum weight of a standard HO 40’ boxcar?
I am wondering if anyone has experimented with weights heavier than the NMRA RP??
Thanks
I mostly do use heavier weights, after all trains usually do carry loads do they not?
I have run hoppers filled with glass beads with no difficulty at all. Many have coal tipples and load their coal cars with real coal. So yes, heavier cars are quite possible.
You identified the issue of the grades, but curves can also be a problem for heavy trains. If there is too much weight at the rear of the train it can ‘string-line’ around the curves. Motive power is also an issue, usually solved by adding more locomotives.
Gross Weights are generally dictated by the capacity of the tracks and roadbed. Somewhat moot in model making you need to experiment with what just seems right for your railroad.
The LION is somewhat indiscriminate in adding weight to his trains, more on the locomotive, somewhat less elsewhere, but the LION eliminated couplers in favor of draw bars on all of his equipment, with wires connecting between the cars. This adds another dimension to tracking which seems to be solved by the extra weight. But the Route of the Broadway LION does have many stiff grades, and some trains must climb these with only one power unit. It needs weight to prevent slipping and Bull Frog Snot to improve traction.
ROAR
My opinion based on my experience:
I am in O scale. NMRA RP for a 40’ car is 15 oz. However I have some cars lighter than that and some much heavier up to 28 oz (1lb 12 oz). I also have broad curves (6ft min on main). If there is a max, it must be pretty high because I have no problems operating a wide variety of weights. Tight turns and non-freerolling wheels would cause issues.
IMO, trackwork, wheel friction and gauge contribute far more to bad operation than weight.
These loaded Athearn hoppers weigh-in at 8oz. each and they’re in regular service. My layout has lots of grades, up to 2.5%, and lots of curves, mostly 34" radius or wider. The loads are loose, but because all cars in the train are the same weight, they don’t seem to cause any difficulties. Locos, of course, need to be doubleheaded.
I briefly ran passenger cars (full-length Rivarossi heavyweights) at 15-20oz., but was concerned that the soft plastic of the sideframes would be damaged by the axle ends. I cut the weight back to about 9 or 10oz. Perhaps if I had better sideframes, I’d increase the weight again - they certainly rolled nicely. [swg]
If you’re adding weight to prevent derailments, your attention would be better directed towards correcting the problems in the track. Then you can run cars light or heavy, with little worry of either causing problems. Generally, it seems more important that all cars in a train be more-or-less the same weight, although carefully blocking your trains to put the heavy cars on the front end and the lighter ones near the rear will allow you to run both in the same train. This works whether you’ve got grades or not.
When that loaded coal train returns south as empties, the cars stay on the tracks just fine, despite weighing just over 2oz. apiece. [swg]
Wayne
I have many cars that are over the NMRA RP. I also have many more cars that are just under the RP. I have superior trackwork, and derailments are very few and very far between. Most derailments are caused by engineer error, mostly by starting and stopping to fast.
An engineer’s skill is more important in my mind than the weight of the cars, as the prototype trains run with loaded and empty, (heavier & lighter) cars scattered throughout the trains. That’s the way I run my railroad. I run DCC and have no momentum programmed in.
To successfully run a train, and keep it on the rails no matter the weight of the trailing cars, you have to start slow building speed gradually, slowing down and stopping the same way. Just like the prototype engineers do.
Gidday, I’ve always, where practicable, stuck to the NMRAs recommended weights for the reason that, cleverer chaps than myself already given considerable thought to the situation besides, unless I have a point to prove, I don’t believe in reinventing the wheel.
The exceptions are flat cars where weight is hard to hide and, as with the rest of my rolling stock, I make sure that the wheel sets are in gauge and bogies are adjusted for good tracking. They don’t appear to give trouble in a consist.
That said and done I have friends who, apart from fitting Kadees and checking coupler heights, run their rolling stock straight out of the box and don’t appear to have too (?) many problems and in fact they reckon I’ve wasted time faffing around with weights and will just wear out the axle pockets in the side frames quicker. Never been sure how scientific their “research” into the excessive wear is though, but it is another reason why I’ve not been game to exceed the NMRA weights. I do have a slight grin when they do concede that they really do like running my “heavy” rolling stock in their consists, though at the front.
As has already been pointed out more weight is not the answer to reliable running, good bench and track work are , in my opinion, the essentials for a great layout
Cheers, The Bear.
Before ANY of my rolling stock hits my layout, they are:
- Brought to NMRA weight specs.
- Checked for proper wheel guage. If they come with plastic wheels, they get replaced with metal ones.
- Coupler height is checked and adjusted. If they’re not Kadees, they get replaced.
- Weathered as I see fit. Some more than others.
Once checked and adjusted, I NEVER have any problems with derailments, other than the human factor (turnouts set the wrong way. Oops!)
We have some (I say some - it’s a whole 24 feeet worth of yard full - over 100 cars) coal hoopers on teh club layout that are well over NMRA weight. They run fine - in fact a model T-1 Northern can pull 100 of them, we run this occasionally but not too often because even with a layout over 110 feet long, it clogs things up. Usual trains are smaller.
Most of my cars are NMRA weight, a few thathave no easy way to open up and add more weight are a little on the light side. I have no issues runnign this, pushing or pulling, through curves and turnouts even at speed. Deliberate sloppy handling does not srem to cause any stringlining on curves, even with a couple of the lighter cars in the middle of the train. I can only conclude that everything is “heavy enough” for reliable operation.
–Randy
Most of the time i run a 25 car train. I have removed at least 1/2 the weight from each car when new. I can pull then with the smallest loco i have 0-4-0. No derailments to speak of. Why lug all that weight around if you don’t need it.? I must have good track work.
Bob