United Kingdom[edit source]
In British practice, railway directions are usually described as up and down, with up being towards a major location. This convention is applied not only to the trains and the tracks, but also to items of lineside equipment and to areas near a track. Since British trains run on the left, the up side of a line is on the left when proceeding in the up direction. The names originate from the early railways, where trains would run up the hills to the mines, and down to the ports.
On most of the network, up is the direction towards London. In most of Scotland, with the exception of the West and East Coast Main Lines, up is towards Edinburgh. The Valley Lines network around Cardiff has its own peculiar usage, relating to the original meaning of traveling up and down the valley. On the former Midland Railway up was towards Derby. Mileposts normally increase in the down direction
On the London Underground geographic direction naming generally prevails (e.g. Eastbound, Westbound), except for the Circle Line where the directions are often referred to as clockwise and anticlockwise.
Individual tracks will have their own names, such as Up Main or Down Loop. Trains running towards London are normally referred to as Up trains, and those away from London as Down. Hence the Down Night Riviera runs to Penzance and the Up Flying Scotsman to Kings Cross.
Other directions commonly used are London and Country. The London end of a station is the end where trains to London depart. The country end is the opposite end, where trains to the country depart. This usage is problematic where more than one route to London exists (e.g. at Exeter St Davids).
see also
http://railway-technical.blogspot.co.uk/2011/08/why-up-and-down.html