Southern Pacific crew cars and all-day-lunch cars

[markpierce]

Can anyone provide information on Southern Pacific crew cars, such as #2802, a 60-C-3 coach rebuilt to a crew car from an all-day-lunch car? Since the car is not included in the roster of coach cabooses, I guess crew cars weren't used as cabooses. What was the purpose of a crew car then? As an accomodation to employees who are deadheading? as a part of a freight or passenger train?

I've read where all-day-lunch cars were sometimes included in express/mail trains to accompany and service the rider coach(s). Were they used elsewhere?