Some of my rolling stock faithfully derailed when backing through a turnout. After checking the wheel flanges I noticed that some were so small as to be non-existent, and others that didn’t are twice their size. What should the “normal” flange depth be running on code 83 rail?
the NMRA Standards and Practices page includes a link to Wheels Standard Scales. See Flange depth (D).
I’ve had that exact same problem at times. Upon closer inspection, I found that the wheels (mostly plastic ones) were so gunked up, they pretty much had no flange. Probably the main reason I replace all plastic rolling stock wheels with metal ones.
My question is this: Which one derails more, the deeper flanged ones, or the ones with little flange?
If the deeper flanged ones have the proper flange depth (or size, whichever term you prefer to use here, only for not making things complicated), than you might have turnouts that are not up to spec.
The thing to watch with metal wheels now: scale size wheelsets. They are narrower, with a smaller flange. They will give me issues with commercial bought turnouts, every time. (The narrower tread will fall into the frog, creating a “bump” that, more often than not, derails that wheelset. And yes, that includes those turnouts that are NMRA spec compliant, as they were fixed to be so.)
Sojourner67, do you have an actual NMRA standards gauge? Use it to check your rail cars, and turnouts. (If you do not have one, get at least one. Before you do anything else layout related.) If your wheelsets do not meet the required specs, as measured by the gauge, fix them or replace them. If your turnouts have issues, (and most commercial turnouts do have at least one area that is out of the specs set by the NMRA), they are fixable.
This may be the key point, and leads me to this question: Are the cars that are having problems fitted with body-mount or truck-mount couplers? Truck-mount couplers, such as those found on older Tyco and Life-Like models, are more prone to derailments when backing, because the forces on the couplers are translated to rotational forces on the trucks themselves, while in body-mount couplers the forces are mostly longitudinal along the car body.
On the subject of metal wheelsets, I agree with the others. They help in a couple of ways. They are a bit heavier, and since all the weight is at the bottom of the car they help with keeping the center of gravity down. More important, perhaps, is the lower rolling resistance. If you’re pushing a string of plastic-wheel cars, there’s a lot more force applied along the couplers than if you’re pushing metal-wheel cars. Even with body-mount couplers, some of that force is lateral when you’re pushing cars through a curve, and that can lead to derailments.
Consistent weight of the cars either to NMRA standards or home brewed standards where weight is a function of car length is important too. Does putting a modest weight on the top of the derailment prone cars change anything for example?
Sometimes it is the combination of one car with another, or one car with a locomotive, that causes all the problems. Swap the cars around and the problem goes away. Presumably has to do with coupler swing and such.
But even with metal wheelsets, wheels all in gauge, flanges all to standards, cars weighted appropriately, body mounted couplers, gauge and guardrails on the turnouts checked – there are just some cussed cars. I can recall reading that I was not the only modeler, for example, who had problems with the old blue box Athearn B&O quad hopper: that there was just something about the way that particular car was engineered that gave it tracking challenges. And a car with a scratchbuild frame gave me problems until I addressed some little errors in placing the bolsters that I had permitted in my haste.
Dave Nelson
My advice buy a NMRA gauge and check the wheel gauge and track gauge simply because your cars could weigh a pound and still derail if the wheels or track is out of gauge.
Another thought… At what speed are you backing? Fast speeds while backing through a switch can cause derailments.
All my car couplers are body mount. That said, most of my cars are yard sale/flea market pickups. There may be quality cars in the bunch but I wouldn’t know. I test them by running them over and through turnouts, and ones that don’t make it get tossed in a box. But among those are a few nice or unique (to me) cars that I’d like to keep. I will try adding some weights. More perplexing is I have a Kato RS and a Rivarossi Heisler that track beautifully through the yard turnouts but a Bachmann F unit derails everytime. Turnouts are Atlas #5’s. And I will pick up a NMRA gauge in the near future.
For weighing cars I have a electric digital scale. Then you can weigh and weight cars to NMRA recommended practice. One ounce plus 1/2 ounce per car body inch.
I do not cut the availible 1/4 ounce car weights, very close is IMO good enough.
Dave