Back to Back dimensions

steve parberry

steve parberry

G Scale Trains
I have had a quick look through here but can not seem to find it so does anybody know what they should be?

Just i have a wide range through my wagons and want to set them for smooth running.

Any help much appreciated
 
It depends on the make (and the make of your track).
 
No - I suppose that is one of the reasons we all have so much fun with pointwork!
 
Ok my standard of 39.75mm must be right:bigsmile::bigsmile:
Seems to work well with LGB, thiel and trainline points

piko points have been banned from use on my railway
 
39.75 - corrr! - thats acurate:thumbup:
Would be 'about 40' on my ruler.:rolf:
 
steve parberry said:
Ok my standard of 39.75mm must be right
Click to expand...
That figure sounds familiar - think it was mentioned over on myLargeScale.com as being the Aristocraft standard, yet someone said their brand new Aristo connie was more like 41mm b2b and wouldn't sit on the rails properly!
 
couldnt find a ruller just me diggy calipers so i have just set twenty wagons to this setting and tested.....they all stayed on the track
 
steve parberry said:
couldnt find a ruller just me diggy calipers so i have just set twenty wagons to this setting and tested.....they all stayed on the track
Click to expand...
Sounds good to me then. I suppose the flange thickness could be different on some makes and that would change the back to back.
 
stockers said:
steve parberry said:
couldnt find a ruller just me diggy calipers so i have just set twenty wagons to this setting and tested.....they all stayed on the track
Click to expand...
Sounds good to me then. I suppose the flange thickness could be different on some makes and that would change the back to back.
Click to expand...
Dosent matter how thick the flanges are the measurment will be the same...i know you are only allowed 2mm on the 12"to the foot scale

1360 to 1362 just in case you wanted to know
 
steve parberry said:
Dosent matter how thick the flanges are the measurment will be the same...i know you are only allowed 2mm on the 12"to the foot scale
Click to expand...
So, How does that work?
if the track gauge is at a set value, & one wheel set has flanges of Xmm thick, a different wheel set has flanges of say (X+3)mm thick, ( exagerated on purpose ')
logically that would mean the back to back of the second set would have to be 6mm less for the gauge to remain the same??
Talking in the model world here, obviously in reality full size railways would have ( in theory) a tighter set of standards for critical dimensions
 
There is a NMRA standard S-4.3

http://www.nmra.org/standards/sandrp/pdf/S-4.3 2010.02.24.pdf < Link To http://www.nmra.org/stand...S-4.3%202010.02.24.pdf

Page 2 of that gives back to back of 40mm with tolerances +0.48 -0.38 (and they also have an imperial measurements table)

It states that the primary controlling dimension is K, the check gauge, but I think measuring this is likely to be difficult in practice.
The NOTES make interesting reading.
 
There is also a European Standard (NEM) published by MOROP

http://www.morop.org/de/normes/nem3...imensions giving Back to back 41.8 to 42.0 mm
 
Granitechops said:
steve parberry said:
Dosent matter how thick the flanges are the measurment will be the same...i know you are only allowed 2mm on the 12"to the foot scale
Click to expand...
So, How does that work?
if the track gauge is at a set value, & one wheel set has flanges of Xmm thick, a different wheel set has flanges of say (X+3)mm thick, ( exagerated on purpose ')
logically that would mean the back to back of the second set would have to be 6mm less for the gauge to remain the same??
Talking in the model world here, obviously in reality full size railways would have ( in theory) a tighter set of standards for critical dimensions
Click to expand...

The crutial point is where the flanges pass through any area with check rails.

As these are normally asociated with the crossing nose(frog) on points the idea is that the flange on the oposite side check rail pulls the wheel near the crossing nose away from the tip, thus ensuring that the axle is taken in the correct direction.
 
Here is the method for simpletons. :bigsmile::bigsmile:

I have points by LGB, Aristocraft and USAT (one of each)

LGB wheelsets run through all of these OK.

I have a plastic LGB wheelset which I keep for when I need to set the back to back on any axle.

I align the backs of the flanges with the Mk1 eyeball. The method has served me well in all gauges from 9mm up to 45 mm, and has never failed.

I also used this method recently when I made my split axles for the pony truck of the 10-wheeler.

Seeemples :thumbup::thumbup::thumbup:
 
You must log in or register to reply here.
Back
Top Bottom