hum...
with an unlimited number of depots etc the industry and research for the same for ammunition, supply, textiles and nitrates would be unnecessary, also the logistical system...
basically you need depots only every third province, or a harbor, or a larger city or a RR. no need to invest that much but in case for colonial action and securing a second line of defense behind the borders
otherwise the half game would be nilled thereby
for RR i agree, no need to cap it, but seriously i played Russia and mostly USA, for the later one i did invest heavily in RR in all populated areas, production centers and for military purpose.
I did not run out of structures and once you have double RR, the number raised again, for the numbers for the caps were identically for RR and double RR while you need a RR to upgrade it to double RR...
even though i did not run out of structures
yeah, the number of buildings are different for different countries, could be found in the scenario file for the GC (its just a educated guess)