work without pay

I work for the U.S. Post Office. Frequently we are required to take collected mail from our outlying office to the main branch. This is not in our job description. We are required to use our own vehicles and we are not compensated for our time in any manner. Is this legal?

You have a union. Are you a member? If so, file a grievance. If not, then you are the one who has to go to your supervisor and protest this. Just remember one thing, even though "they" say and are trying to run the U.S. Post Office as if it were a completely private corporation, there is still a great deal of "politics" involved.