Hi Sturm
The gist of it is that Birago gear and/or its derivatives were used by virtually everybody all over the world. After WW1 vast stocks of it ended up in a great many armies. In Poland it would not have been perhaps the first choice, but having inherited huge stocks of serviceable gear, a poor army like the Polish one could not ignore them. So they were pressed into service, albeit bits and bobs were modernised progressively (for example the wooden load-bearing beams were replaced with lighter and more robust RSJs) and missing/worn-out elements (such as wagons) were replaced, sometimes with locally-designed and often different gear. This undoubtedly went on in many if not most armies in Central Europe and ended up in Axis hands either by alliance or capture. Consequently it takes a real expert (aka a dedicated rivet-counter

) to differentiate between the different versions. And, alas, few rivet counters get excited by engineering equipment......
That was one of the reasons I was hounding poor George about photo 756. Circa 1936 the Sapper Department in Poland concluded there was much to be gained from replacing wooden wheels with pneumatic ones on the bridging column wagons. Photos are rare as hen's teeth and I have never seen an original wagon thus upgraded. The wheels look like Polski Fiat wheels to me and the wagon could be a Birago job, so......