Labor Law - Collective Bargaining and the USPS

Have you ever considered what would happen if all the mail carriers who work at the post office all went on strike at the same time? Well, you do not have to worry about that because it is against the law for them to do so.
Still, they have a Letter Carriers Union, which does have quite a bit of strength, especially in numbers and the United States Post Office, which is a quasi government agency is indeed, compelled to listen and take each and every grievance seriously.
How big is the United States Post Office? You wouldn't believe it if I told you, but here is a very scary statistic, which you may find interesting.
The United States Post Office has the largest fleet of vehicles in the entire world.
What happens when the postal workers are not happy with their working environment? Well, we all know that when employees are not happy, their efficiency goes down, which is something that cannot happen, because, the mail must go on; "Rain or Shine!" If a Postmaster or Manager at a Post Office gets too many grievances, they are terminated or moved to a different facility.
Of course, each grievance is reviewed.
Not long ago, I met a gentleman who had actually filed over 3,000 grievances with the post office, while acting as the head of the local union for a city about the size of 150,000 in population.
He indicated that he often had mail carriers come to him with complaints that were not actually grievances of bad management, but rather just an upset employee embellishing the situation.
Nevertheless, of his 3,000 grievances filed 10% were challenged, and he had a perfect record of winning those that were challenged, which leads me to believe that they were all legitimate.
Still, in looking at this record it was over a 30-year period, meaning that he only filed 100 per year, so, this goes to show you the strength of the letter carriers union and the excellent stewardship that is involved in its unions.