SazModel Code 55 #6 Turnouts

Would you like some ready to run turnouts? What kind?

Code 55 #6
6
38%
Code 55 #8
8
50%
No thank you
2
13%
 
Total votes : 16

Re: SazModel Code 55 #6 Turnouts

Postby j p » Fri Apr 25, 2014 2:09 am

gerhard_k wrote:
Bernd wrote: it gives answers to questions of "how did they do that".
Bernd

At 2:00: Amazing how that small steel weight brings it up to 1/48th of the weight of the full-size car - let's see, that would be about 37,000/48 = 770 lb !
I can't believe that nobody caught that... :naughty:


Weight is a 3D material property, so for 1/48, the correct scaling would be 1/110592.
27,000 lb in your example would turn to 0.334 lb for a 1/48 model.
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Re: SazModel Code 55 #6 Turnouts

Postby Marquette » Fri Apr 25, 2014 9:02 am

Seeing as I don't know the equation there to calculate the weight for a 1/120 model... but I'm getting this idea that most TT freight cars are overweight then?
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Re: SazModel Code 55 #6 Turnouts

Postby Marquette » Fri Apr 25, 2014 11:10 am

Okay I don't get it. 110592 is 48^3, but 1/48 = 0.02083, and 0.02083 * 0.02083 * 0.02083 = 0.0000090379... so I don't get how you're figuring that.

But then I'm dumb. :)

Also, that is irrelevant to my original comment ... :P I meant, cars being overweight in terms of scale weight!

If a 1/48 car should be 0.334 lbs to be to scale weight, that's 5.344 oz ... which number should then be considerably smaller than 4 oz for a 1/120 car to be in scale - thus TT scale cars are overweight! :D
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Re: SazModel Code 55 #6 Turnouts

Postby j p » Fri Apr 25, 2014 11:33 am

Marquette wrote:Okay I don't get it. 110592 is 48^3, but 1/48 = 0.02083, and 0.02083 * 0.02083 * 0.02083 = 0.0000090379... so I don't get how you're figuring that.

But then I'm dumb. :)

Also, that is irrelevant to my original comment ... :P I meant, cars being overweight in terms of scale weight!

If a 1/48 car should be 0.334 lbs to be to scale weight, that's 5.344 oz ... which number should then be considerably smaller than 4 oz for a 1/120 car to be in scale - thus TT scale cars are overweight! :D


That was for an empty car.
For a loaded car in TT, I take a brass Joma tank car as an example since I am just applying decals to one:
LTWT 45,900 + CAPY 80,000 makes a total of 125,900 lb.
To get that to TT, just divide it by 120 three times because you scale length, width, and height.
It is 0.0728 lb (1.166 oz).
NMRA says 3/4 oz + (3/8 oz x length in "), that is 0.75 + (0.375 x 3.6) = 4.725 oz. corrected: 2.1 oz
Conclusion: Yes, TT cars are overweight if they follow NMRA standard.

But!
I checked the real weight of that particular car and it was 0.90 oz. It was empty indeed, I have not filled any oil in it :lol:
So you can very well get all your cars very close to their (loaded) scale weight.
My cars do not follow the NMRA weight standard.
Last edited by Anonymous on Sun Apr 27, 2014 3:35 pm, edited 2 times in total.
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Re: SazModel Code 55 #6 Turnouts

Postby milwrd1 » Sun Apr 27, 2014 1:52 pm

j p wrote:
That was for an empty car.
For a loaded car in TT, I take a brass Joma tank car as an example since I am just applying decals to one:
LTWT 45,900 + CAPY 80,000 makes a total of 125,900 lb.
To get that to TT, just divide it by 120 three times because you scale length, width, and height.
It is 0.0728 lb (1.166 oz).
NMRA says 3/4 oz + (3/8 oz x length in "), that is 0.75 + (0.375 x 3.6) = 4.725 oz.
Conclusion: Yes, TT cars are overweight if they follow NMRA standard.

But!
I checked the real weight of that particular car and it was 0.90 oz. It was empty indeed, I have not filled any oil in it :lol:
So you can very well get all your cars very close to their (loaded) scale weight.
My cars do not follow the NMRA weight standard.


For TT scale, NMRA RP 20.1 recommends an initial weight of 3/4 oz + (3/8 oz additional weight per inch of car body length).
The frame of the brass Joma Tank car is 3 and 3/16 inches long, or 3.1875 inches. (Approximately 36.5 feet in TT scale).
3/8 is 0.375. 0.375 times 3.1875 = 1.195 ounces, + .75 = 1.945 ounces. This is the NMRA recommended weight for the brass Joma tank car. Note in jp's calculation above, 0.375 x 3.6 does not equal 4.725, it equals 1.35.

I added 0.17 oz of lead to the underframe of the brass Joma tank car with a resultant TOTAL weight (including trucks and couplers) of 1.15 ounces. Considering the added weight, this is close to jp's measured weight of 0.90 oz.

Based on the above, the brass Joma tank car, even with additional weight added, is underweight per the NMRA recommended practice.
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Re: SazModel Code 55 #6 Turnouts

Postby Marquette » Sun Apr 27, 2014 3:28 pm

milwrd1 wrote:Based on the above, the brass Joma tank car, even with additional weight added, is underweight per the NMRA recommended practice.


Which is the opposite way of answering my question, that yes, the models are overweight in terms of scale weight. :)
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Re: SazModel Code 55 #6 Turnouts

Postby j p » Sun Apr 27, 2014 3:33 pm

milwrd1 wrote:
j p wrote:
That was for an empty car.
For a loaded car in TT, I take a brass Joma tank car as an example since I am just applying decals to one:
LTWT 45,900 + CAPY 80,000 makes a total of 125,900 lb.
To get that to TT, just divide it by 120 three times because you scale length, width, and height.
It is 0.0728 lb (1.166 oz).
NMRA says 3/4 oz + (3/8 oz x length in "), that is 0.75 + (0.375 x 3.6) = 4.725 oz.
Conclusion: Yes, TT cars are overweight if they follow NMRA standard.

But!
I checked the real weight of that particular car and it was 0.90 oz. It was empty indeed, I have not filled any oil in it :lol:
So you can very well get all your cars very close to their (loaded) scale weight.
My cars do not follow the NMRA weight standard.


For TT scale, NMRA RP 20.1 recommends an initial weight of 3/4 oz + (3/8 oz additional weight per inch of car body length).
The frame of the brass Joma Tank car is 3 and 3/16 inches long, or 3.1875 inches. (Approximately 36.5 feet in TT scale).
3/8 is 0.375. 0.375 times 3.1875 = 1.195 ounces, + .75 = 1.945 ounces. This is the NMRA recommended weight for the brass Joma tank car. Note in jp's calculation above, 0.375 x 3.6 does not equal 4.725, it equals 1.35.

I added 0.17 oz of lead to the underframe of the brass Joma tank car with a resultant TOTAL weight (including trucks and couplers) of 1.15 ounces. Considering the added weight, this is close to jp's measured weight of 0.90 oz.

Based on the above, the brass Joma tank car, even with additional weight added, is underweight per the NMRA recommended practice.


Yes, we both got it wrong. NMRA weight is 2.1 oz.
I calculated it wrong and you measured the length wrong. My caliper shows 92.79 mm which is 3.653 in inches.
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Re: SazModel Code 55 #6 Turnouts

Postby j p » Sun Apr 27, 2014 3:50 pm

Marquette wrote:
milwrd1 wrote:Based on the above, the brass Joma tank car, even with additional weight added, is underweight per the NMRA recommended practice.


Which is the opposite way of answering my question, that yes, the models are overweight in terms of scale weight. :)


No, that would be a misunderstanding.
Most models are OK in terms of scale weight (for cars). I used Joma tankcar in the example also because its weight is average and because it does not need any additional weight for good performance.
The only two models overweight in scale weight would be Kemtron 2-bay offside hopper and Gandy Dancer 40' boxcar - the version with all parts made of cast metal.

All locomotives would be overweight in terms of scale weight. I would not recommend making the locomotives in correct scale weight simply because the friction of the trucks of the cars is not in scale, it is much higher.
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Re: SazModel Code 55 #6 Turnouts

Postby milwrd1 » Sun Apr 27, 2014 4:59 pm

Sure did measure incorrectly. :thumbdown: The frame is 3 and 11/16 inches, or 3.6875. The corrected info is presented below:

For TT scale, NMRA RP 20.1 recommends an initial weight of 3/4 oz + (3/8 oz additional weight per inch of car body length).
The frame of the brass Joma Tank car is 3 and 11/16 inches long, or 3.6875 inches. (Approximately 36.5 feet in TT scale).
3/8 is 0.375. 0.375 times 3.6875 = 1.383 ounces, + .75 = 2.1328 ounces. This is the NMRA recommended weight for the brass Joma tank car.

I added 0.17 oz of lead to the underframe of the brass Joma tank car with a resultant TOTAL weight (including trucks and couplers) of 1.15 ounces. Considering the added weight, this is close to jp's measured weight of 0.90 oz.

Still, the conclusion is correct. Based on the above, the brass Joma tank car, even with additional weight added, is underweight per the NMRA recommended practice.
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Re: SazModel Code 55 #6 Turnouts

Postby milwrd1 » Sun Apr 27, 2014 5:14 pm

j p wrote:
Marquette wrote:
milwrd1 wrote:Based on the above, the brass Joma tank car, even with additional weight added, is underweight per the NMRA recommended practice.


Which is the opposite way of answering my question, that yes, the models are overweight in terms of scale weight. :)


No, that would be a misunderstanding.
Most models are OK in terms of scale weight (for cars). I used Joma tankcar in the example also because its weight is average and because it does not need any additional weight for good performance.
The only two models overweight in scale weight would be Kemtron 2-bay offside hopper and Gandy Dancer 40' boxcar - the version with all parts made of cast metal.

All locomotives would be overweight in terms of scale weight. I would not recommend making the locomotives in correct scale weight simply because the friction of the trucks of the cars is not in scale, it is much higher.


This has not been my experience. Most of the older, vintage TT scale freight cars perform better when weight is added, to make the weight closer to the NMRA recommended values. The all metal Kemtron hopper and the all metal version of the Gandy Dancer boxcar do not require any weight for good performance. I look at each piece of rooling stock on an individual basis. I believe that most TT engines would be overweight in terms of scale weight. I don't know if NMRA RP 20.1 was supposed to address locomotive weights.
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