Editing Locomotive frame (section)

== Articulated locomotives ==
{{Main article|Articulated locomotive}}

An [[articulated locomotive]] with no fixed wheels (i.e. excluding the [[Mallet locomotive]] but including other articulated [[steam locomotive]]s, as well as most [[diesel locomotive|diesel]] and [[electric locomotive]]s) may have a separate frame beneath the superstructure, or the bodywork's internal structure may be load-bearing.   Rarely is a true [[monocoque]] structure used.

Diesel and electric locomotives with a traditional, full-width body, known as [[cab unit]]s in [[North America]], tend to have their strength in an internal structure.  This style of construction is still popular elsewhere, but North American locomotives nowadays are overwhelmingly [[hood unit]]s&mdash;with a strong frame beneath the superstructure that carries all the load, and bodywork made of removable panels for easy maintenance. Fully enclosed locomotives are used in some limited applications, mostly for [[passenger train]]s. These tend to be [[cowl unit]]s, in which the body is not load-bearing.