Weight question

Davidfd85 Nov 16, 2014

  1. Davidfd85

    Davidfd85 TrainBoard Member

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    Ok this might be one of those obvious questions but I need to ask it any way to make sure. If the weight of each car is done with the 1 oz plus 1/2 oz per inch formula to get the correct scale weight on say a 10 car train that could get a bit heavy. Now the weight could cause the engine to lose traction and spin the drive wheels. If I am thinking right. So how would you make sure your engines are the correct weight? Take the actual weight, by model of engine, and divide it by .87 or .087. And also would this help in the pulling of the correct weighted cars too.
    I am thinking the correct weight engines would help with traction and pulling the correct weight cars.

    And also how would you add weight to the engines (Diesels). With the stick on weights like I am planning to use on the cars?

    Thanks
    David
     
  2. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

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    Interesting question. On level track, would adding weight to your cars actually cause that much of a problem? Adding weight to your motive power will be restricted by space available, and also any electronics in the way. Can you really add enough, to make a difference? I presume that your cars are all equipped with the most freely rolling trucks and or wheel sets?
     
  3. Davidfd85

    Davidfd85 TrainBoard Member

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    That is where I am asking myself the questions. Will adding the weight cause a problem, that I am not sure of. I see people talking about following the NMRA standards for car weights but I have never seen anything said about the engine weights. If one is close to prototypical (cars) and the other is not (engines) then it does not make sense to me. They should both be as close to prototypical as possible in my mind. Then also comes the question the difference between the weight of empty cars vs loaded cars. How can this be modeled in scale as far as weight goes.
    Having the free rolling trucks are something I will work on and change if I can figure out if it is worth all the trouble with the questions I have in my own mind, ie. Is really worth all that work.

    Thanks

    David.
     
  4. BoxcabE50

    BoxcabE50 HOn30 & N Scales Staff Member TrainBoard Supporter

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    Hmmmm. One idea would be to go ahead and add weight to about ten or a dozen cars, then see how those effect your power's pulling abilities. See what happens when there is a grade, curves, going through yard ladder switches. You'd have just a minimum of effort and money invested. This would give a small idea of anything undesired, or deficiencies. Attach any weights so they could easily be removed, if you disliked the results.
     
  5. gjslsffan

    gjslsffan Staff Member

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    I have no doubt that adding the weight will help with operations for you.
    These locos have weight added as room allowed, and all cars have weights added and free rolling truck wheel combinations. These were necessary, so string line issues could be dealt with. Here is a channel that shows some videos of what I refer to. It also helps with wobbling and rocking issues to a degree. Free rolling truck wheel combinations are very important when adding weight to your rolling stock. Sheet lead under the Flat cars and stick on weights in boxcars and poured in steel shot for hoppers and tank cars secured with Elmer's glue was our approach. I went down to a local industrial tire store and bought 1/4 and 1/2 oz stick on weights by the 25 lb box. It was not that expensive compared to buying from LHS.

    We rate 6 powered axles on the 2% at 12 cars and 4 axle units at 10 cars. They certainly work and slip a bit on the climb but its kinda neat to see them work so hard to get the trains to the top.

    [video]https://www.youtube.com/user/gjslsffan[/video]

    Regards
    Tom


     
    Last edited by a moderator: Nov 16, 2014
  6. Ironhorseman

    Ironhorseman Staff Member In Memoriam

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    Can you add more motive power as do the protos?
    Still ... and interesting thought you have !
     
  7. gjslsffan

    gjslsffan Staff Member

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    Yessir I sure can. All the locos are geared and set up to work together, I have ran up to 13 locos but it was just too much tractive effort. We have found that 5-6 locos is the limit before you start pulling cars off the rail behind the power (string line). I like to take visitors up to the top of the 2% grade uncouple the power from the train and let them pull the train by hand a few inches, it is incredible what those little HO locos will pull. I have a 50+ car coil steel train that I made coils from heavy wall pipe for the loads (4 each car) used 8" of pipe cut into 3/4" lenghts to make the coils. It is so heavy 5 SD's wont pull it up the 2%, so we use helpers on the rear, or sometimes we cut them in ahead of 10 cars. Its an interesting thing to operate.
    Regards

     
  8. John Smith

    John Smith TrainBoard Member

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    Weighing cars to NRMA standards doesn't mean you are actually weighing the cars to 1:87 the weight of an actual railcar. It is just a standard that is used to have the most trouble free operations. e.g.- shoving a cut through a double crossover up a grade. NRMA standards have changed over the years... and , they could change again. I think you should test your locos with the weighted cars before adding weight to the loco. I have a 1% grade... and with two Athearn AC4400s, I can pull 20 loaded(loose coal loads in the hoppers/gondolas) that are weighted to NRMA standards with no problem(HO scale). The locos will slow down when they encounter the grade and pull all the way to the top. I can add some throttle if I want the train to stay at track speed... however, I like it when they slow down and struggle on the grade... so to speak. I have no problems pulling 30 loaded hoppers, although, then I DO need to add throttle, otherwise the trains slips, and can stall. JMS
     
  9. gjslsffan

    gjslsffan Staff Member

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    Just out of curiosity, what would be the formula be? Say the LD LMT /87, /87/ 87?
     
  10. Ironhorseman

    Ironhorseman Staff Member In Memoriam

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    "We have found that 5-6 locos is the limit before you start pulling cars off the rail behind the power (string line)."

    Yes ... I'm sure that's a result of 'tight' curves on our model railroad that are not capable to resist the lateral force trying to make a straight-path line. Several years ago, there was an incident on UPee's line going up the Shasta Block in an area known as, The Cantara Loop, Siskiyou County, CA; where several tank cars were pulled off of the rails and fell into the Sacramento River. You have the answer though when you use 'pusher(s)' and/or cut power into the consist. Wish I could see your layout! :)

    At one time, early on when I first started the hobby I would add weight as you have only to learn the metal axles would wear out the hole(s) in the plastic trucks, which made the cars come off the track due to the instability. Solution: replace the trucks.
     
  11. gjslsffan

    gjslsffan Staff Member

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    Thanks David, this is an interesting thread for sure.
    There is a youtube link at bottom of this post to videos of my MRR. 48" minimum radius curves, they are mostly 56" and a couple 72" on the main tracks #8 turnouts and xovers, #6 minimum in the yards. There is a couple vids on the building and layout, although there has been a lot of scenery work since some of these videos.
    I have learned making these videos is more work that I thought it would be LOL.

    https://www.youtube.com/user/gjslsffan
     
  12. John Smith

    John Smith TrainBoard Member

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    Not really sure what the equation is... but, just dividing by 87 would mean a fully loaded railcar(286K lbs.) would weigh 3287 lbs. when scaled down to HO. LOL! JMS
     
  13. Davidfd85

    Davidfd85 TrainBoard Member

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    I can't remember what the equation is right now and haven't looked for it but I think the number is either .87 or .087 to get it down to HO scale. Either way it still comes out ridiculously high, so guess the NMRA standards are not meant to be taken literately. It is just one of those things that makes you wonder.

    Thanks
    David
     
  14. kb9lww

    kb9lww New Member

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    Weight is a function of volume. Volume of a rectangular block is figured as length times width times height, and expressed in cubic units. So to find the scale weight of your 286,000 lbs car you should divide by 87 cubed (658,503). The result is 0.44 lbs or approximately 7 ounces. If your car is 12 inches long, that's right on the money.

    According to thedieselshop.us an SD70 weighs 394,000 lbs. Using the same formula an HO scale one would weigh 0.598 lbs or about 9.5 oz.
     
  15. John Smith

    John Smith TrainBoard Member

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    Thanks! It seems the railcars are close... but, 9.5 oz. for a locomotive... seems light to me... I guess I will weigh my locos and see what is what for those! JMS
     

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