The National Postal Transport Association (NPTA) was a labor union representing workers in the Postal Transportation Service in the United States. The union was founded in 1898 as The National Association of Railway Postal Clerks, and was chartered under the laws of New Hampshire as a fraternal beneficiary association. In 1904 the name was changed to the Railway Mail Association. A section of the union split away in 1911, to form the . In 1917, the union was chartered by the American Federation of Labor, and in 1919 it absorbed the railway postal clerk section of the .