Knowing that the grab iron on the side of the car has defined dimension between bolt holes allows simple proportional determination of the effective width of the siding.
Quite simple: (dimension 'A'/known) = ( dimension 'B'/unknown) Optics of the scanner or other viewing device are of no consequence. This is why known 'story sticks' are often used in photographing artifacts.
The AAR drawing is a keeper, thank you for that one.
BillD Wrote:
=======================================================
>
> Another point... Rex was in error to say that you
> should scan the plans and scale them up and
> measure the length... this would magnify any
> errors in either the plans or the scanning (often
> scanning will "stretch" one axis more than the
> other). This is why you should never scale
> anything from a plan, and why good plans are
> always fully dimensioned.
>
> Bill Daniels, P.E.
> San Francisco, CA
Rex Beistle
NMRA RMR
Estes Valley Division