A Travelling Post Office (TPO) was a type of mail train used in Great Britain and Ireland where the post was sorted en route. The TPO can be traced back to the earlier days of the railway, the first ever postal movement by rail being performed by the Liverpool and Manchester Railway (L&MR) on 11 November 1830. The Railways (Conveyance of Mails) Act 1838 obliged railway companies to carry mail, and thus specialised rolling stock was quickly provided; the first true TPO emerged that same year. Further innovations followed, such as the development of lineside apparatus for picking up and setting down mailbags while underway, and the use of dedicated mail trains. By 1914, there were 126 TPO carriages in operation throughout the United Kingdom, while numerous other nations had adopted the concept, wholly or in part, as well. During the latter part of the twentieth century, rail mail was subject to various changes. In Britain, Rail Express Systems (RES) was formed during the 1980s to rejuvenate the market, streamlining and centralising rail mail services, resulting in TPO coverage decreasing over the following years. During the 1990s, the Royal Mail, Britain's main customer for TPOs, ordered 16 four-car British Rail Class 325 electric multiple units to replace locomotive-hauled counterparts in handling parcels. However, wider economic factors, including increasingly effective mechanical sorting methods in comparison to the TPO's manned sorting, along with operational safety concerns, made it increasingly unattractive to continue operating such services. Accordingly, the final regular TPO service in Great Britain was performed on 9 January 2004, with the carriages themselves used sold for scrap or to preservation societies. Since then, the Royal Mail has occasionally transferred some mail by rail, but has preferred using aircraft or road vehicles for doing so. History Origins On 11 November 1830, the first ever postal movement by rail was made by the Liverpool and Manchester Railway (L&MR), which had come to an agreement with the General Post Office (GPO) to move their mail upon L&MR services. It quickly became apparent that the railways were providing a much faster method of conveying letters across the country than traditional horse-drawn coaches. Accordingly, the carriage of mail by train in Great Britain became a routine event within a matter of years. Initially, the movement of mail was at the choice of individual railway companies, being able to accept or refuse to do so at their