Editing Trackless train (section)

==Technology==
[[Image:Duxfordtransporter.jpg|thumb|[[Van]]-hauled trackless train at the [[Imperial War Museum Duxford]], [[England]]]]
A trackless train usually consists of a [[tractor unit]] pulling a number of articulated [[Trailer (vehicle)|trailers or carriages]] in the manner of a [[locomotive]]-hauled [[railway]] [[train]]. The tractor unit can be powered by an [[internal combustion engine]] or an [[electric vehicle|electric motor]]. Trackless trains using [[Human-powered_land_vehicle|human power]] are generally driven not only by the tractor but also by the carriages.

Carriages may seat between 6 and 40 persons, and can be roofed or not, featuring open or closed sides and various levels of interior comfort such as padded seats. If open, depending on climate they may feature plastic or fiberglass corrugated panels overhead, to divert rain and provide some measure of shade. Alternative designs may use a cloth [[awning]] overhead for similar purposes.

Carriages usually contain latchable doors or chains to act as safety measures to prevent exit while in motion. Carriages and tractor false bodies may be constructed in [[fiberglass]] or aluminum, and may feature levelling [[Suspension (vehicle)|suspension]].

As in a regular road vehicle, the tractor unit is steered through the front wheels by a [[steering wheel]] or handle bar operated by a human driver, and powered by its rear single or double [[axle]]. The following carriages are then steered through the [[Drawbar (haulage)|drawbar]] couplings between the carriages. Simple trains with few carriages or short in overall length may feature single- or double-axle carriages with just front-axle steering only. Larger or longer trains feature [[four-wheel steering]] by way of [[Linkage (mechanical)|mechanical linkages]]. Four-wheel steering ensures that longer trains need less side clearance while turning, as the carriages are able to maintain the same path, describing a constant radius of [[Arc (geometry)|arc]]. This adds to the impression of the vehicle being on rails. The drawbar connections of more complex trains may feature a [[shock absorber]] to mitigate the effect of [[acceleration]] or [[braking]].
[[File:PathDiagramThunerTrampelwurm.svg|thumb|Thuner Trampelwurm: path of the complete road train turning left 90°]]
The longest trackless trains appear to be human-powered ones. In 2007 a train of 93 tricycles was assembled and ridden for the purpose of setting a world record.<ref>{{cite web
| url = http://www.hase-spezialraeder.de/64-1-world-record-2007.html
| title = World record
| date = 2010
| publisher = Hase Bikes
| accessdate = 2013-05-31
| url-status = dead
| archive-url =https://web.archive.org/web/20111007210608/http://hasebikes.com/64-1-world-record-2007.html
| archive-date = 2011-10-07}}</ref>
The train was formed by removing the single front wheels of the tricycles used as carriages and attaching their forks to the tricycle in front. This system developed for [[Hase_Spezialräder|Hase tricycles]] and others also allows the ad-hoc formation of shorter trains for practical use. The longest permanently set up human-powered trackless train is probably the Thuner Trampelwurm consisting of a tricycle as tractor with 10 driven trailers as carriages, in operation as a tourist attraction in the city of [[Thun]] since 1994. The chosen geometry of the trailer linkages result in good tracking at the cost of a low maximum speed, about 10 km/h without [[Speed_wobble|shimmy]].<ref name="BS4">{{cite book | title = Bicycling Science | url = https://mitpress.mit.edu/9780262538404/bicycling-science/ | edition = Fourth | last = Wilson | first = David Gordon | author2 = Theodor Schmidt | year = 2020 | publisher = The MIT Press | isbn = 978-0-262-53840-4 | page = 489}}</ref>