Passenger rail transport is the conveyance of passengers by means of wheeled vehicles specially designed to run along railways. Trains allow high capacity or short or long distance, but require track infrastructure and stations to be built. Urban rail transit consists of trams, light rail, rapid transit, people movers, commuter rail and funiculars. Typical railway tracks consist of two parallel rails, normally made of steel, secured to crossbeams, termed sleepers (UK and Australia) or ties (U.S. & Canada).
The sleepers maintain a constant distance between the two rails; a measurement known as the gauge of the track. To maintain the alignment of the track it is either laid on a bed of ballast or else secured to a solid concrete foundation. The whole is referred to as permanent way (UK and Australia usage) or right-of-way (North American usage). Railway rolling stock, which is fitted with metal wheels, moves with low frictional resistance when compared to road vehicles. On the other hand, locomotives and powered cars normally rely on the point of contact of the wheel with the rail for traction and adhesion (the part of the transmitted axle load that makes the wheel adhere to the smooth rail).
While this is usually sufficient under normal dry rail conditions, adhesion can be reduced or even lost through the presence of unwanted material on the rail surface, such as moisture, grease, ice, or dead leaves. A travel class is a quality of accommodation on public transport. Higher travel classes are more comfortable and more expensive. Not all modesand operators offer class differentiation. The sleeping car or sleeper is a railroad passenger car that can accommodate all its passengers in beds of one kind or another, primarily for the purpose of making nighttime travel more restful. The first such cars saw sporadic use on American railroads in the 1830s and could be configured for coach seating during the day. Some of the more luxurious types have private rooms, that is to say fully- and solidly-enclosed rooms that are not shared with strangers.
Trains can travel at very high speed; however, they are heavy, are unable to deviate from the track and require a great distance to stop. Although rail transport is considered one of the safest forms of travel, there are many possibilities for accidents to take place. These can vary from the minor derailment (jumping the track), a head-on collision with another train and collision with an automobile or other vehicle at a level crossing/grade crossing.
Level crossing collisions are relatively common in the United States where there are several thousand each year killing about 500 people (the comparable figures in the United Kingdom are 30 collisions and 12 casualties). For information regarding major accidents, see List of rail accidents.The car is divided into a number of compartments (typically 8 or 9) accessed from the side corridor of the car, which in daytime are configured with a bench seat along each long side of the compartment.
At an appropriate time in the journey, the attendant who travels in the car (or by agreement the passengers booked in the compartment) converts the compartment into its night-time configuration with two (1st class) or three (2nd class) bunks on each long side of the compartment, creating a total of four bunks in first class and six in second class. Typically, in the 2nd class the seat serves as the lowest bunk, and the back of the seat is turned into a horizontal position and serves as the middle bunk.
Urban rail transit is an all-encompassing term for various types of local rail systems serving urban or older suburban areas. The vast majority of modern urban rail vehicles run on electricity. The set of urban rail systems can be roughly subdivided into four categories, which sometimes overlap, causing some systems or lines to have aspects of each, International trade is in principle not different from domestic trade as the motivation and the behavior of parties involved in a trade does not change fundamentally depending on whether trade is across a border or not The main difference is that international trade is typically more costly than domestic trade. The reason is that a border typically imposes additional costs such as tariffs, time costs due to border delays and costs associated with country differences such as language, the legal system or a different culture.