If I were a historian of the San Juan Extention (which I am not), one of the things that would be on my list of things to do would be to interview Amos Cordova or any of his contemporary agents on the DRGW ng. and get some history of how the paper work was handled. This was just as much an integral part of the railroad as things like running trains, dispatching, and the telegraph, etc. Bills of Lading got signed between customers and the railroad, waybills were prepared to authorize the movement of cars, and freight bills got paid. Some freight presumably moved prepaid, apparently a lot of stuff moved to Aztec and Farmington COD. How all this got done over time might be an interesting bit of history. Or it might not be. But I wonder if it has ever been documented. Text books have been written about the theory, but how it actually got done at the local level might be a whole different story. Like the demurrage that didn't get charged for. In my experience SP paid a whopping fine to the ICC once for not properly charging demurrage. It was a tariff item, and deviations from the tariff were frowned upon......but happened all the time.
When it comes to the ng., no detail is too small to be ignored.
JBWX