The 5.5mm Association has a 5.5mm ruler at:
http://www.blackhamtransfers.com/55/55mmAssn/5andahalfrule.html
I scale from plans. The easiest way is to scan the plans and change the scale on a copier.
Harold
I gotta say Harold, this is interesting! When you scale out, say a flatcar, what measurements do you use? Do you use a scale rule (if so, what scale?) or do you just use an inch rule. How wide would you make the typical car? Since I do like modeling something different, I may try a locomotive and a car or 2, just to check it out.
This looks like it has possibilities...
The site was down because of a new web host. We are promoting the use of HO track at a scale of 5.5mm/foot for three foot narrow gauge.
We are at:
http://www.55n3.org/
Thank you if you visit