My uncle Jack was in charge of a mail crew that sorted mail on the train. I always thought he worked for the post office but when my aunt passed away I helped go through her things and the retirement he got was from the railroad not the postal service.
Yes the mail was far more efficient than it is now.
Interesting! I didn’t know that the post office contracted out that function to the railroad. But it makes sense when you think about it. The focus was on providing superior service, not public employee union jobs.