Wheel, Rail

History: A train wheel or rail wheel is a type of wheel specially designed for use on rail tracks. A rolling component is typically pressed onto an axle and mounted directly on a rail car or locomotive or indirectly on a bogie (UK), also called a truck (North America). Wheels are cast or forged and are heat-treated to have a specific hardness.
Railroad car wheels are affixed to a straight axle, such that both wheels rotate in unison. This is called a wheelset.

Wheels and wheelsets are found in various diameter and axle length. This variety is also reflected in model trains.
The most common axle lengths for N scale model trains vary from 0.538 inch (MTL) to beyond 0.576 inch (Arnold-Rapido). See this blog article for more details on N scale wheelsets.

Railroad/Company: This set of items is comprised of more than one name. Please look at the component items for details on the specific roadnames and/or manufacturers.