The technology and systems used draw from both British and North American systems. Structure and rollingstock gauges are clearly influenced by the British railway practice, as are braking systems. Wagon couplings on freight trains are predominately auto couplers with friction wedge type draft gear packages showing the North American influence. Privately owned railways on iron ore mines in the Australia’s North West show even more North American influence with American style braking and larger structure and rollingstock gauges. Australia is also characterized by three track gauges a legacy of colonial and state governments before federation. The presence of narrow gauge of 1067mm, results in a large fleet of rollingstock with design differing from standard gauge rollingstock in North America, Britain and the southern states of Australia.The chapter is arranged to firstly give an overview of longitudinal train dynamics.The second section goes into considerable detail on approaches to modelling longitudinal train dynamics. The most space is given to the modelling of the wagon connection model. Sub-sections are also devoted to modelling traction and dynamic braking systems, rolling resistance, air resistance, curving resistance, the effect ofgrades and pneumatic braking. The sub section on pneumatic braking only provides an explanation of the effect of pneumatic braking on train dynamics. Modelling pneumatic braking systems would require a chapter in itself. Further more brief chapter sections are included on the interaction of longitudinal train dynamics with lateral/vertical wagon dynamics, crashworthiness, comfort and train managementand driving practices.