Re: Qs Generated by a Shorpy Photo ...
I would take note of age, car owner, car outline. The car with the narrower running boards is also a few inches narrower than the others...when you mix 36', 40' 50' etc. in the same train, when you have varying degrees of car widths too due either construction era or home road (look at a X29 vs the same era Western car), when the older a car is, the drier (usually) the boards get, the more "character" is evinced.
The real issue is though not only does the physics not scale as Dennis noted, but the boards width and warping isn't apt to scale (as much). Looking at the boards, some are warping one way, other another - one reason the drawings show specific grain patterns for specific boards in specific places/ The drawings don't just show the base construct, but there is far more to them - the scrap diagrams and the wood grains are critical in learning why a car was built in a specific way - and why and how they age. This is not unlike determining crown and laying the wood - or instilling a crown (by saw or cast) such that the load bears "on top of" the crown.
Most running boards on HO models are one piece - or three. Rarely do people make the effort of actually using three pieces of wood - in the proper sequence and grain pattern . If you are going to speak of variety in terms of the roof though, that's the granularity you are going to have to get to. Note that if you do as some of us did 40 years ago - scribing then shaving the inside of the "boards" to duplicate this (in our heads, anyway) - you end up with ...shaved plastic looking like ...nothing natural.
If you look at the photo, the 2d, 5th & 7th cars are all narrower - and have narrower running boards. When built, they were likely in proportion and within the standards. As cars got wider, the boards got wider. The saddles got wider - think the opposite of airline seat evolution. Too...check out the 7th & 8th cars - those appear to be much shorter, much narrower cars. The photo makes it look like that's 1 car - but check the brake staffs. So...you are looking at two sets of boards - not one that is widely varied. Looking at roofs is a fine thing - regardless. But in context it may make more sense.
At 12:12 PM 9/15/2019, you wrote: