The first official mail transport by rail in the world occurred in 1830 when the UK's General Post Office shipped mail on the Liverpool and Manchester Railway. Then, in 1838, the General Post Office again achieved another first when the first Travelling Post Office car was introduced on the Grand Junction Railway, enabling sorting of mail while en route. Here in the US, the first mail was carried in a baggage car in 1831 on the South Carolina Rail Road, and Congress designated all US railroads as official postal routes in 1838. In 1862, the Hannibal and St. Joseph Railroad began regularly carrying mail in purpose-built mail cars. But it was August 28, 1864, that interests us most today, because that was the date that George B. Armstrong, a postmaster who had been promoted through his service in Chicago, established the first permanent RPO route in the US. It wasn't much longer until RPO cars looked more like what we think of today, as the mail hook was patented in 1867. The last regular RPO service in the US ended on June 30, 1977, with the last run of the route between New York and Washington, DC.