The Hope Valley Railroad has a Mail Car similar to one my Grandpa worked on throughout his career with the Railway Mail Service.
Grandpa explained to us how he would sort the mail based on postal codes, and place it in bins like these.
Here is a tray full of mail.
Here is the mail hook that was used to catch mailbags hanging from posts along the tracks. The mail clerks could drop the outgoing mail bag out the door onto the ground and snag the incoming mailbag and the train never slowed down.
Good advice.
