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Railroad directions are used to describe train directions on rail systems. The terms used may be derived from such sources as compass directions, altitude directions, or other directions. However, the railroad directions frequently vary from the actual directions, so that, for example, a "northbound" train may really be headed west, or a train going "down" may actually be increasing its elevation. Directions are often specific to system, country, or region.
In France, railway directions are usually described as Impair and Pair (meaning Odd and Even), corresponding to Down and Up in the British system. Impair means heading away from Paris and Pair means heading toward Paris. This convention is applied not only to the trains and the tracks, but also to items of lineside equipment.
Pair is also quasi-homophonic with Paris, so direction P is equivalent either with direction Pair or with direction Paris.
In China, railway directions are described as "up" (上行) and "down" (下行), with up towards Beijing; trains leaving Beijing are "down", while those going toward Beijing are "up". For railways not connected with Beijing, north and west are used as "up" and east and south as "down". Odd numbered train codes are used for "down" trains, while even numbers are used for "up"; for example, train T27 from Beijing west to Lhasa is "down" (going away from Beijing) since 27 is odd.
Trains run through Beijing may have two or more numbers, for example, the train from Harbin to Shanghai K58/55 uses two different numbers: In the Harbin-Tianjin section, the train runs toward Beijing, the train is known as K58, but in Tianjin-Shanghai section, the train is known as K55; the opposite train from Shanghai to Harbin is known as K56/57, while K56 is used from Shanghai to Tianjin and K57 is used from Tianjin to Harbin.
In Japan, railway directions are referred to as "up" (上り nobori?) and "down" (下り kudari?), and these terms are widely employed in timetables and station announcements for the travelling public. For JR Group trains, trains going towards the capital Tokyo are "up" trains, while those going away from the capital are "down" trains. For private railway operators, the designation of "up" or "down" (if at all) usually relies on where the company is headquartered as "up".
For loop lines, such as the Yamanote Line in Tokyo and the Osaka Loop Line, directions are usually referred to as "outer" (外回り soto-mawari?) and "inner" (内回り uchi-mawari?), where trains go clockwise on the outer track and counter-clockwise on the inner track.
In Hong Kong practice, the "up track" refers to northbound, and the "down track" refers to southbound. This old practice on the British Section of the Kowloon-Canton Railway, now called the East Rail, is followed on the West Rail. In other words, trains towards the city centre of Kowloon is the "down" direction instead of the "up direction ". "Northbound" and "southbound" are, nonetheless, more commonly used.
On the original metro network of the MTR, platforms for the general direction towards the depot are numbered with odd numbers, whereas platforms for the opposite direction are numbered with even numbers. Depots are usually located on or near the end of MTR lines. Exceptions are stations that are located further than the depot, e.g., the stations of Ngau Tau Kok and Kwun Tong on the Kwun Tong Line.
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 travelling 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 or the loop of the Central line where the directions are often referred to as inner rail (anti-clockwise) or outer rail (clockwise).
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).
Most railroads in the United States use nominal cardinal directions for the directions of their lines which often differ from actual compass directions. These directions are often referred to as "railroad" north, south, east or west to remove ambiguity with the same compass directions.
Typically an entire railroad system (the lines of a railroad or a related group of railroads) will describe all of its lines by only two directions, either east and west or north and south. This greatly reduces the possibility of misunderstanding the direction in which a train is travelling as it traverses lines they may twist and turn or even reverse direction for a distance. These directions also have meaning in conflicts between trains running in opposite directions. For example, many railroads specify that trains of equal class running east are superior to those running west. This means that, if two trains are approaching a passing siding on a single-track line, the inferior westbound train must "take the siding" and wait there for the superior eastbound train to pass.
In the United States, most railroads use "east and west". It is unusual for a railroad to use "north and south".
Even numbered trains (superior) travel east (or north). Odd numbered trains (inferior) travel west (or south). An easy way to remember this: "ODD trains go to San Francisco (west). VERY ODD trains go to Los Angeles. (south)"
In many commuter rail and rapid transit services, the rail directions are related to the location of the city center. The term inbound is used for the direction to go in toward the city center and outbound is used for the opposite direction to go out of the city center. In New York City, the term uptown and downtown are used in the subway to refer to northbound and southbound respectively. The actual railroad direction, however, is determined with how the line will travel when it enters Manhattan.
- Train numbers
- JR Timetable, March 2012 issue
- Ferry, J. Amanda. "Boston's subway". Boston.com. Retrieved 31 October 2013.
- "Muni Metro Map". The San Francisco Municipal Transportation Agency. Retrieved 31 October 2013.
- "How to Ride the Subway". Metropolitan Transportation Authority. Retrieved 31 October 2013.