discretion. The passing of the Railways (Conveyance of Mails) Act 1838 substantially reshaped the rail mail market. Chiefly, it required all railway companies to carry mail, either by ordinary or special trains, as required by the Postmaster General; however, this act did not stipulate what was to be charged for such services. In addition to making it mandatory for railway companies to carry mail, the act also required the provision of carriages fitted for sorting it as required; to handle this new obligation, these companies quickly developed specialised rolling stock for the task. According to industry periodical Rail Magazine, the first Travelling Post Office (TPO) carriage emerged during 1838, and credited George Kastadt, a surveyor employed by the GPO, with the concept. On 6 January 1838, Kastadt proposed a trial of a ‘travelling office’, of which the first run was conducted just weeks later. The advantage of this innovation was that time could be saved by sorting mail while it was being transported, rather than separately sorting it either beforehand or afterwards and thus taking more time to do so. This initial TPO was a converted horse box and was initially operated on the Grand Junction Railway. Karstadt's son was one of two mail clerks who did the sorting. During 1845, the Midland Railway decided to extend their TPO services via Derby to Newcastle upon Tyne; and soon after reached Scotland. The first special postal train was operated by the Great Western Railway between London and Bristol; the inaugural train ran on 1 February 1855, leaving Paddington station at 20:46, and arriving at Bristol at 00:30. Prior to 1885, it was common practice for TPO carriages to be added to consists of normal passenger services. That same year, the first dedicated Mail Special was conducted. Early on, the TPOs were relatively barebones in terms of their onboard facilities. Internal space was limited and prioritised for the principal purpose of sorting mail, thus measures to enhance staff comfort was typically more of an afterthought. Initially, toilets were not even provided, although this position was reportedly reversed after the accidental death of a postal worker while relieving himself at the rear of a TPO. Expansion and decline While rail mail had emerged in Britain, the country was quickly followed by many of the member nations within the British Commonwealth along with various third party countries. TPOs were usually equipped with letter boxes,