Back when I was in the stations department, I travelled a lot as we had 80 customer service centers over the system. My job took me to all the larger ones and when I got back in town there would be 4-5 inches of paper in my inbox. To try and keep up with this correspondence I’d toss it all in a brief case and read it on the plane. Much of it was merely reading files with a list of names stapled to it. You’d cross off your name and the file was routed to the next by an office clerk. The railroad, for internal correspondence, never used US Mail. Everything moved by company mail in a 1,000 mile envelope. You’d put your correspondence in a large envelope, write the name on who it was going to on a space on the back and it had a string to tie it shut. Company mail moved in cabooses and it don’t recall ever seeing it get lost. Late maybe but never lost.

The railroad also had its own telephone system that used the old telegraph lines. Later in the 1970’s they converted to microwave. On some parts of the railroad
It sounded like you were talking down a steel barrel on the old lines but generally they were pretty good. There was a ‘message’ line into the telegrapher/operator and a dispatcher line. The message line was the RRs party line so you heard everyone conversations.

The good old days before email and cell phones.