Quite by accident, I came upon this 07/09/1926 issue of The Postal Bulletin which provides an alphabetical listing of all RPO (Railway Post Office) titles and abbreviations in use as of that date (list appears on pages 10-12):
http://www.uspostalbulletins.com/PD...19260709.pdfFor US RPO (Railway Post Office) cover collectors, I thought this alphabetical listing might come in handy to bookmark, especially on those occasions when one may come across an old RPO postmark with a name that is difficult to read.