A mooring post used on the concrete wall at Oakland, Cal. – from – Wharves and piers: their design, construction, and equipment pg. 189 pub 1917.
When I looked at the dimensions of the concrete footing I realized that the ones I had created for my scene were smaller. The ones in the drawing are 4 ft. square at the base tapering up to where the bollard flange is bolted down. That flange is 3 ft. on a side. That’s 3/4 in. in O scale and I measured my concrete footings and found they were 5/8 in. Okay .. soooo .. with that in mind I rescaled the original so the bollard flange would have about a 1 in. (0.020 in) smaller then the top of the concrete footing.