RPPC’s — that is, real-photo postcards — are often one-of-a-kind, taken by amateur photographers of strikingly local subjects simply because they were there. There is also a reasonable expectation that an RPPC is unique.
I looked on eBay this evening for photographic images of bridges in rural settings, the sort of bridges easily found in an early 20th century setting in places like Fennimore, bridging the Mighty Muskrat or one of its several feeder streams like Crispin Creep. But simple search terms like “RPPC bridge) yielded more than 6,000! from which I chose these two.
The photo of the longer hybrid bridge (spanning a river, rather than a stream) also shows a weir (a submerged dam) and adjacent water-powered mill building. This is potentially very useful, since Agincourt had such a pairing, but also for the technology it reveals —even in this distant hazy view. And also for the question that follow from it: When was the state involved in establishing a hierarchy of roads [much like the British B, A, and M levels] and who regulated the type and carrying capacity for bridges? The history of civil engineering is well outside my experience.