Back in August 1826 Rowland Hill had first suggested the sorting of letters on mail coaches, but this came to nothing. With the advent of the railways, George Karstadt, a long-standing Post Office surveyor, made a formal proposal on 6 January 1838 to trial a 'travelling office' where mail could be sorted into the required bags en route. The first run took place later in January 1838, on the Grand Junction Railway from Birmingham to Liverpool, using a converted horse box.

After the experiment had been running for a few months a purpose-built carriage was proposed and built. Drawings of the carriage appeared in the Illustrated London News, with the comment:

"Here is a specimen of that exhaustless ingenuity which bids fair to annihilate time and space an improvement which enables the Post Office to practically work double tides, in other words to duplicate time by travelling and working at the same instant".

From the outset the purpose-built Travelling Post Office (TPO) was fitted with an apparatus to drop and pick up mail bags while the train was still moving. In May 1838 the Post Office tried out an apparatus devised by Post Office clerk John Ramsey. It consisted of an iron frame covered by a net and attached to the TPO carriage. This opened out to receive a bag suspended from the arm of a standard, or gibbet erected at the side of the railway line. At the same time as a bag was delivered into the net another was dropped. The first experiment was regarded as very successful, and it was introduced generally on 5 March 1839.

Ramsey's original device was improved, but the overriding principle of 'drop and grab' lasted until 1971 when this apparatus was finally taken out of service. The image below shows a Victorian TPO crew standing next to the mailbag transfer net fitted to a Great Western railway carriage.

Illustration

TPO staff outside a GWR carriage