U.S. Scott 853, the New York World's Fair issue, with Royal Train RPO postmark and Railway Mail Service (RMS) cancel. The cover was mailed on June 6, 1939 aand received at the Hotel McAlpin in New York City on June 9, 1939. It has a scarce U.S. use of the Perfect Machine cancel with a Universal Machine receiving mark. There is staining where the seams of the envelope were glued (see scans).
U.S. Scott 853 on 1939 Royal Train RPO Railway Mail Service Cover
Returns accepted for up to 30 days from the date of mailing, for any reason, as long as the item is returned in the same condition that it was sent.