I have seen this question-and-answer before but I have forgotten to write it down. What is the formula for rollingstock weight? I know it’s so much weight per inch of car. Please help.
thanks, Rob
Here’s a good way to remember and use the NMRA guideline: It’s one ounce to start with plus an additional 1/2 ounce for every inch of car length (or .5 x car length- which is easier to calculate- use decimal inches!). What you do is to buy one of those inexpensive battery-operated digital readout food scales with a clear weight surface, then print out a small label with the following: 1 oz+ .5(car decimal length) and fix it on the scale somewhere (but not on the weighing surface/plate). 1/8th inch = .125, 3/8th inch = .375, etc.
Using this method, a 5-1/2 inch car needs 1 oz. plus 2.75 ozs.= 3.75 ozs. (as per NMRA guideline).
Then, you won’t forget the arithmetic and after a few uses, you will know it automatically!
Harbor Freight and Bed/Bath/Beyond are 2 places to easily find these scales. I use mine regularly (and they come in handy for dieting[:D]).
More seriously, I don’t use it for motive power, as the NMRA guideline is for rolling stock. I also will weigh all parts of a car kit (Athearn BB, etc) WITH the metal wheels I will be using, before I start building; then add weight while everything is on the scale until I reach the NMRA calculated weight goal. (measure the length of the car from frame end to frame end, not coupler to coupler. Flat cars are a bit trickier- if you plan a permanent load on board, calculate and weigh WITH the load (where you can often also hide additional weight).
It is also a good idea to go back over existing built/RTR rolling stock in your inventory and review each car’s weight- sometimes the RTR’s or those swap meet purchases need a bit of additional weight themselves! Keep a list and work on them as you can- it’s a great series of easy projects for rainy days/weekends.
Cedarwoodron