This set of six Post & Go stamps focuses on the transportation of mail by railway, and coincides with the 90th anniversary of the Post Office Underground Railway, which opened in time for Christmas 1927. Four of the stamps depict various aspects of the Travelling Post Office, which ran from 1838 until 2004 - bag exchange, loading, sorting and 'on the move'. The final two stamps depict the Post Office Underground Railway and a poster for the classic GPO Film Unit's Night Mail documentary, made in 1936.
This cover carries an image of the inside of a sorting carriage of the Travelling Post Office. The stamps are cancelled with a pictorial Ullswater Road, Penrith handstamp for the location of the last mailbag exchange.
