鉄道郵便局
The National Postal Transport Association (NPTA) was the successor to the Railway Mail Association. The name change was prompted by the United States Post Office Department reorganizing the Railway Mail Service as the Postal Transportation Service on October 1, 1949. In 1961, the NPTA merged with the National Federation of Post Office Clerks (NFPOC) and the United National Association of Post Office Clerks (UNAPOC) to form the 115,000-member United Federation of Postal Clerks (UFPC).