Joint support of Post Office and Amtrak to allow Amtrak to move the mail again. Congress removed the authority for Amtrak to serve mail or express business with rail transport of mail. This impacts the Post Office that it can not take advantage of the lower cost of rail movement of mail. This restriction was put in place to insure that airlines, private mail and express firms would face no competition and could charge any price for their service. 1 RR mail car carries more than 5 big trucks.