In the years of the post-Amtrak Southern Crescent, the dining and lounge car crews were based in Atlanta. The train ran overnight, every night Atlanta-Washington, and tri-weekly Atlanta-New Orleans. As far as the dining cars were concerned, there were five regular crews that ran on the following cycle (the “crew numbers" are not official; just as a reference):
Crew 1, Crew 2, Crew 3 - one long cycle per week, which consisted of going on duty in Atlanta with the fresh dining car, leaving on train 1 for New Orleans. The crew overnighted in New Orleans, worked through Atlanta on train 2 the next day, arriving Washington the next morning, and after an all-day layover, worked back overnight on train 1 to Atlanta. They were off for the rest of the week until their cycle began on the same day of the following week.
Crew 4, Crew 5 - two short cycles per week. These crews worked two Atlanta-Washington turn-around trips per week, leaving Atlanta on train 2, arriving Washington the next morning, working south from Washington on train 1 that evening, and arriving the next morning in Atlanta.
There was also a dining car extra board where people could fill in as needed for vacation or sick day relief, or be added when heavier passenger loadings were expected.
Post-Amtrak, the tavern car only operated Atlanta-Washington, and I remember only two positions for that service, where the attendants made a turn-around trip every other day. There had to have been some provision for their relief somewhere along the line with an extra board attendant, but how it worked into the scheme escapes me at present. You could not put just anybody into that job - they had to have some experience keeping inventories and handling money, which was beyond the pay grade of a dining car waiter. IIRC, the position of the Southern Crescent’s lounge car attendant was a “waiter-in-charge”, which was the same position as the person in charge of a dinette-coach or a stripped down dining car with a two-man crew - a waiter-in-charge and a chef; no steward.