Editing Rail transport operations (section)

==Extrinsic factors==
Rail transport systems are built into the [[landscape]], including both the [[physical geography]] (hills, valleys, etc.) and the [[human geography]] (location of settlements). The rail transport system may in turn feedback into the human geography.

===Physical geography===
The [[permanent way]] of a system must pass through the geography and [[geology]] of its region. This may be flat or mountainous, may include obstacles such as water and mountains. These determine, in part, the intrinsic nature of the system. The slope at which trains run must also be calculated correctly. In this stage, it is decided where [[tunnel]]s pass.

===Human geography===
Rail transport systems affect the human geography. Large cities (such as [[Nairobi]]) may be founded by a railroad passing through. Historically, when a station has been built outside the town or city it is intended to serve, that town has expanded to include the station, or buildings (especially [[Inn]]s) sprung up near the station. The existence of a station may increase the number of [[Commuting|commuters]] who live in a town or village and so cause it to become a [[dormitory town]]. The [[first transcontinental railroad|transcontinental railroad]] was a large factor in American [[colonization]] of the [[American frontier|Western frontier]]. [[Qinghai–Tibet Railway|China's railroad expansion]] into [[Tibet]] may have similar consequences.

===Historical factors===
Rail transport systems are often used for purposes they were not designed for, but have evolved into due to changes in human geography. [[Politics]] can play a large part in decisions about railways, such as the [[Beeching Axe]]. In the [[United Kingdom|UK]], building or rebuilding a railway usually requires an [[Act of Parliament]]. In many countries, [[rail subsidies]] allow unprofitable, but socially desirable, railways to continue to operate.