In 1859 as a further means of accelerating the mails “the limited mail” train was started. Many people have doubtless wondered at this definition of an express train: they have probably connected it in some way with the idea of speed, but in reality it was nothing more than the application of the old regulation of the mail coach days to railway traffic. That is to say, the mails were to be the first consideration, and the passenger traffic was to be limited on these trains to the point where the speed or the availability of the train for mail purposes would not be interfered with. The first limited mail to run was the night train to Scotland. An advance on the idea of the limited mail was made in 1885, when a special mail train was established on the London and North-Western and Caledonian Railways. This is a train devoted entirely to the mail service, and it runs in both directions between London and Aberdeen. Similar special trains run on the Great Western Railway between London and Penzance. One of the latest developments of the system is the provision of a late-fee box on the side of the carriage. The letter-box on the side of the carriage next to the platform is kept open while the train is standing in a station. The up-to-date sorting carriages are an immense improvement on those of the old pattern in the matter of easy movement. They are constructed with a view to reduce vibration to a minimum. All projections and angles are well padded, and this precaution is at all times necessary, as turning a curve at high speed frequently takes the sorters off their feet and sends them flying into corners or against the sides of the carriage. In the new sorting carriages plate-glass bottoms are provided for the letter-sorting frames to enable the sorters to see at a glance that they have removed all the correspondence from each box at the time of despatch. This prevents letters being carried beyond their destination or left in the carriage at the journey's end. The duty of each officer is laid down in detail in the “duty book,” as is also “the plan” or “alphabet” he is to use in sorting the correspondence, and the order in which the bags are to be hung. Every man knows exactly what he has to do, and that he must depend upon his own exertions for the completion of his duty over every stage of the journey. Space is necessarily limited. Along one side of the letter-vans are pigeon-holes for sorting purposes, while the opposite side is fitted with pegs for holding the bags and with the machinery used for the exchange apparatus.