It seems that if I place a newer gondola car (very light) between a few of the heavier box cars I get derailments from that car at the O curve. Is that a common issue?
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Yes. You have to operate your model trains much like real trains. Nice and slow when starting. Once up to speed string lining shouldn't be so bad, but it will still happen if the lead cars are too light.
Yep, heavy in front, light in back. Norfolk Southern keeps learning that lesson on Horseshoe Curve with their center beam lumber cars. 
Or…you could weight all your cars to NMRA standards. That was the single best thing I ever did to improve operations.
I'm sure the NMRA improves the performance of individual cars but that seems like a lot of weight to add to a multiple car train.
@Freight Train Jim posted:I'm sure the NMRA improves the performance of individual cars but that seems like a lot of weight to add to a multiple car train.
If you are using modern cars it really doesn’t effect performance very much unless you have a serious grade problem. A few years ago I had an all day project weighing and adding weight, as necessary, bringing all cars to NMRA standard. I have had virtually no derailments pulling or pushing trains even through multiple crossovers.
Adding weight per NMRA standards helps= as does body mounted couplers…
Here's one way to think about it. Every car on the train has to bear the weight of every single car behind it.
@Danr ,
What did you use for the weights?
stick on car wheel weights?
@Rick Stoffregen posted:Adding weight per NMRA standards helps= as does body mounted couplers…
Do body mounted couplers raise the minimum curve a car can negotiate? I'm interested in this for better operations but I'm worried I'll lose my minimum radius abilities where I need them.
Rich and Danr, I've weighted cars as I take them out of storage for use, or upon procurement of new cars before going into storage. I've noticed many of the traditional size rolling stock are about 11" long which makes for a 1 pound car when weighted. Some of my die-cast seem to weigh more than that. Have you experienced any issues running die-cast and weighted cars together?
@texgeekboy posted:@Danr ,
What did you use for the weights?
I used Harbor Freight 1/4oz self-adhesive wheel weights. 48 pieces in a pack for $10.
@BillYo414 posted:Do body mounted couplers raise the minimum curve a car can negotiate? I'm interested in this for better operations but I'm worried I'll lose my minimum radius abilities where I need them.
Yes. The longer the car, the larger the required radius. Look at the overhang and current coupler displacement of your cars and imagine a fixed coupler with a relatively short shank. An 18" car will likely work on 072 curves. Anything less than 072, an "S" curve or an 072 crossover will result in binding.
@coach joe posted:Rich and Danr, I've weighted cars as I take them out of storage for use, or upon procurement of new cars before going into storage. I've noticed many of the traditional size rolling stock are about 11" long which makes for a 1 pound car when weighted. Some of my die-cast seem to weigh more than that. Have you experienced any issues running die-cast and weighted cars together?
Occasionally you may find a diecast car that is a little overweight but, once you get all of the cars to NMRA spec, there is very little difference - diecast and plastic will work just fine together.
@Danr posted:Yes. The longer the car, the larger the required radius. Look at the overhang and current coupler displacement of your cars and imagine a fixed coupler with a relatively short shank. An 18" car will likely work on 072 curves. Anything less than 072, an "S" curve or an 072 crossover will result in binding.
Well darn it. I hope I can convert without losing the ability to go all over the layout. Thanks for the info though!
The NMRA RP20.1 standard specifies rolling stock weight of 5 oz plus 1 oz per inch of car length. They do no distinguish between 2 rail scale and 3 rail hi-rail, though I suspect the standards are actually for 2-rail. When you follow the standards, the cars end up heavier than most ready to run cars. Weighting the cars to standard significantly adds to the overall pulling power required on hills, but also on trying to start a train, and traversing a curve. For this reason I also avoid buying diecast rolling stock.
While the extra weight is needed in the 2 rail world of scale wheel flanges, it is generally not needed with our oversize 3-rail flanges. I rarely add weight to any rolling stock other than Weaver (most are way too light, although you can get away without adding weight if you only run Weaver cars at the end of the train). Still the advice of locating heavier cars in the front of the train is sound. Since I run a mix of 2-rail and 3 rail rolling stock, I also locate the 2 rail cars closer to the rear of the train to reduce string-lining risk.
Despite all of this effort, I once ran a scale Erie Triplex pulling 25 hoppers with loads. It kept derailing the car directly behind the tender. I switched out the car multiple times and the problem recurred. I finally figured out that the derailments were from the combination of the tender coupler swing and the excessive stiffness of the coupler. I ended up putting a diecast hopper behind the tender to solve the problem.
Bob
I typically weigh my cars to NMRA standards and change over to body mounted couplers. Especially on weaver cars. They (40 footers) have no problem rolling around 042 curves and easily traverse gargraves and ross turnouts. The extra weight keeps them from climbing over the switch frog. I have one kline diecast hopper that has to go to the front of the line since it weighs nearly 2 pounds.
@third rail posted:I typically weigh my cars to NMRA standards and change over to body mounted couplers. Especially on weaver cars. They (40 footers) have no problem rolling around 042 curves and easily traverse gargraves and ross turnouts. The extra weight keeps them from climbing over the switch frog. I have one kline diecast hopper that has to go to the front of the line since it weighs nearly 2 pounds.
The recently released UP Rocket Train Set has a similar issue. The buffer boxcars weigh one pound, but the rocket carriers weigh over two pounds. Add to that Lionel used fixed couplers with no swivel between the truck and coupler, and it can be a problem.
