Editing Bogie (section)

== Railway ==
A ''bogie'' in the UK, or a ''railroad truck'', ''wheel truck'', or simply ''truck'' in North America, is a structure underneath a [[railway vehicle]] (wagon, coach or locomotive) to which axles (hence, wheels) are attached through [[Bearing (mechanical)|bearing]]s. In [[Indian English]], ''bogie'' may also refer to an entire [[railway carriage]].<ref>{{cite web|url=http://www.oxfordadvancedlearnersdictionary.com/dictionary/bogie|title=Oxford Learner's Dictionaries - Find definitions, translations, and grammar explanations at Oxford Learner's Dictionaries|website=www.oxfordadvancedlearnersdictionary.com|access-date=8 May 2018|url-status=dead|archive-url=https://web.archive.org/web/20110807101435/http://www.oxfordadvancedlearnersdictionary.com/dictionary/bogie|archive-date=2011-08-07}}</ref> In [[South Africa]], the term ''bogie'' is often alternatively used to refer to a freight or goods wagon (shortened from ''[[bogie wagon]]'').
[[File:Jervis' Bogie Locomotive.jpg|thumb|left|''Experiment'', the first successful American locomotive with a bogie,  built in 1831 to a design by civil engineer [[John B. Jervis]]]]
A locomotive with a bogie was built by engineer [[William Chapman (engineer)|William Chapman]] in 1812. It hauled itself along by chains and was not successful, but Chapman built a more successful locomotive with two gear-driven bogies in 1814.{{Citation needed|date=November 2023}} The bogie was first used in America for wagons on the Quincy Granite Railroad in 1829. The first successful locomotive with a bogie to guide the locomotive into curves while also supporting the [[smokebox]] was built by [[John B. Jervis]] in 1831. The concept took decades before it was widely accepted but eventually became a component of the vast majority of mainline locomotive designs. The first use of bogie coaches in Britain was in 1872 by the Festiniog Railway. The first standard gauge British railway to build coaches with bogies, instead of rigidly mounted axles, was the [[Midland Railway]] in 1874.<ref>{{cite book |last=Jenkinson |first=David |author-link=David Jenkinson |title=British Railway Carriages of the 20th Century - Volume 1: The end of an era, 1901-22 |year=1988 |publisher=Guild Publishing |location=London |id=CN 8130 |page=10 }}</ref>

===Purpose===
[[File:Bogie Vehicle Schematic-en.svg|thumb|Bogies allow the [[Wheelset (rail transport)|wheelsets]] to more closely follow the direction of the rails when travelling around a curve in the railroad.]]
[[File:Indirect truck.gif|thumb|200px|Displacements of a bogie]]
Bogies serve a number of purposes:<ref name="how">{{cite journal | author = Isao Okamoto | date = December 1998 | title = How Bogies Work | journal = Japan Railway & Transport Review | issue = 18 | pages = 52–61 | url = http://www.jrtr.net/jrtr18/pdf/f52_technology.pdf | url-status = dead | archive-url = https://web.archive.org/web/20070927202523/http://www.jrtr.net/jrtr18/pdf/f52_technology.pdf | archive-date = 2007-09-27 | access-date = 2018-11-30 }}</ref>
* supporting the body of the rail vehicle
* running in a stable manner on both straight and curved track
* improving [[ride quality]] by absorbing vibration and minimizing the impact of centrifugal forces when the train runs on curves at high speed
* minimizing generation of track irregularities and rail abrasion.

Instability can occur when a combination of bogie design, springing, vehicle and bogie wheelbase, and track dynamics, cause the bogie to oscillate at high speed – a phenomenon known as "hunting". If unchecked, derailment can occur. Cars experiencing hunting are removed immediately once the defect is discovered. A tendency for more than one vehicle to hunt will result in investigations with a view to re-designing.<ref>{{cite book |title= South Australian Railways annual report 1946-47 |date= 1947 |location= Adelaide |publisher= [[South Australian Railways]] |page=17 }}</ref>

Usually, two bogies are fitted to each [[Railroad car|carriage]], wagon or [[locomotive]], one at each end. Another configuration is often used in [[articulated vehicle]]s, which places the bogies (often [[Jacobs bogie]]s) under the connection between the carriages or wagons.

Most bogies have two axles,<ref name="how" /> but some cars designed for superior riding qualities or heavy loads have more axles per bogie. Heavy-duty cars may have more than two bogies using [[span bolster]]s to equalize the load and connect the bogies to the cars.

Usually, the train floor is at a level above the bogies, but the floor of the area between the bogies may be lowered to increase interior space while staying within [[Loading gauge|height restrictions]]. Examples are [[Well car|container well cars]], [[bilevel rail car|bi-level passenger cars]] or stepless-entry, low-floor cars on railways with near-ground-level platforms.

===Components===
{{Main| List of railroad truck parts}}
[[File:Railroad truck, FM55-20.Fig8-8.png|thumb|A diagram of an American-style truck showing the names of its parts and showing the [[journal box]]es to be integral parts of the [[Truck side frame|side frame]].<ref>{{cite web|url=https://patents.google.com/patent/US1924237A/en|title=Bogie truck for railway and like vehicles|website=google.com|access-date=8 May 2018|url-status=live|archive-url=https://web.archive.org/web/20180508093532/https://patents.google.com/patent/US1924237A/en|archive-date=8 May 2018}}</ref><ref name="col">{{Cite web |title=AAR M-1003 Certified Truck Component Manufacturing |url=http://www.columbuscastings.com/bolster_frames.html |url-status=dead |archive-url=https://web.archive.org/web/20141019033202/http://www.columbuscastings.com/bolster_frames.html |archive-date=2014-10-19 |access-date=19 November 2014 |website=ColumbusCastings.com |publisher=Columbus Castings |location=Columbus, Ohio}}</ref><ref name="SCT">{{Cite web |date=January 2000 |title=General Information |url=http://www.sctco.com/pdf/sect_1.pdf |url-status=dead |archive-url=https://web.archive.org/web/20160304045504/http://www.sctco.com/pdf/sect_1.pdf |archive-date=4 March 2016 |access-date=19 November 2014 |website=SCTCO.com |publisher=Standard Car Truck Company}}</ref> The journal boxes house [[plain bearing]]s.]]
Key components of a bogie include:<ref name="how" />
* The bogie frame: This can be of inside frame type where the main frame and bearings are between the wheels, or (more commonly) of outside frame type where the main frame and bearings are outside the wheels.
* [[suspension (vehicle)|Suspension]] to absorb shocks between the bogie frame and the rail vehicle body. Common types are [[coil spring]]s, [[leaf spring]]s and [[rubber]] [[Air suspension|airbags]]. 
* At least one [[Wheelset (rail transport)|wheelset]], composed of an axle with [[Bearing (mechanical)|bearings]] and a wheel at each end.
* The [[List of railroad truck parts#Truck bolster|bolster]], the main crossmember, connected to the bogie frame through the secondary suspension. The railway car is supported at the pivot point on the bolster.
* Axle box suspensions absorb shocks between the axle bearings and the bogie frame. The axle box suspension usually consists of a spring between the bogie frame and axle bearings to permit up-and-down movement, and sliders to prevent lateral movement. A more modern design uses solid rubber springs.
* [[Brake (railway)|Brake equipment]]: Two main types are used: [[brake shoe]]s that are pressed against the tread of the wheel, and [[Disc brake#Railroad and tram use|disc brakes]] and pads.
* In powered vehicles, some form of [[Transmission (mechanics)|transmission]], usually electrically powered [[traction motor]]s with a single speed gearbox or a hydraulically powered [[torque converter]].

The connections of the bogie with the rail vehicle allow a certain degree of rotational movement around a vertical axis pivot (bolster), with side bearers preventing excessive movement. More modern, bolsterless bogie designs omit these features, instead taking advantage of the sideways movement of the suspension to permit rotational movement.<ref name="how" />

==== Locomotives ====
===== Diesel and electric =====
{{Main|UIC classification of locomotive axle arrangements|AAR wheel arrangement}}
Modern [[diesel locomotive|diesel]] and [[electric locomotive|electric]] locomotives are mounted on bogies.  Those commonly used in North America include [[AAR type A switcher truck|Type A]], [[Blomberg B|Blomberg]], HT-C and [[Flexicoil]] trucks.<ref>{{cite web|url=http://www.hosam.com/emd/emd6a.html|title=trucks|website=www.hosam.com|access-date=8 May 2018|url-status=live|archive-url=https://web.archive.org/web/20160409141649/http://www.hosam.com/emd/emd6a.html|archive-date=9 April 2016}}</ref>

===== Steam =====
On a [[steam locomotive]], the [[Leading wheel|leading]] and [[trailing wheel]]s may be mounted on bogies like [[Bissel truck]]s (also known as ''pony trucks''). [[Articulated locomotive]]s (e.g. [[Fairlie locomotive|Fairlie]], [[Garratt locomotive|Garratt]] or [[Mallet locomotive|Mallet]] locomotives) have '''power bogies''' similar to those on diesel and electric locomotives.

==== Rollbock ====
{{main|Rollbock|Transporter wagon}}
A rollbock is a specialized type of bogie that is inserted under the wheels of a rail wagon/car, usually to convert for another [[track gauge]]. Transporter wagons carry the same concept to the level of a [[flatcar]] specialized to take other cars as its load.

==== Archbar bogies ====
In archbar or diamond frame bogies, the [[List of railroad truck parts#Truck side frame|side frames]] are [[metal fabrication|fabricated]] rather than [[cast steel|cast]].
<gallery mode="packed" heights="160px" caption="Archbar bogie pool">
File:Oigawa-Archbar-Truck.jpg|Japanese archbar bogie with [[axlebox]]es
File:Diamond Frame bogie (elliptical).jpg|Diamond frame bogie, [[elliptical spring]]s and American style [[journal box]]es
File:Diamond Frame bogie (coil).JPG|Diamond frame bogie, [[coil spring]]s and [[journal box]]es
File:archbar ACL143.JPG |Archbar bogie with [[journal bearing]]s in American style journal boxes, as used on some steam locomotive tenders. Archbar bogies (trucks) were also used on [[Railway car#Freight cars|freight cars]].
</gallery>

=== Tramway ===

==== Modern ====
[[File:Septa PCC car truck.jpg|thumb|Side view of a [[SEPTA]] K-Car bogie]]

[[Tram]] bogies are much simpler in design because of their axle load, and the tighter curves found on tramways mean tram bogies almost never have more than two axles. Furthermore, some tramways have steeper gradients and vertical as well as horizontal curves, which means tram bogies often need to pivot on the horizontal axis, as well.

Some [[articulated tram]]s have bogies located under articulations, a setup referred to as a [[Jacobs bogie]]. Often, [[low-floor tram]]s are fitted with nonpivoting bogies; many [[tramway enthusiast]]s see this as a retrograde step, as it leads to more wear of both track and wheels and also significantly reduces the speed at which a tram can round a curve.<ref>{{cite web |url=http://www.railway2007.fd.cvut.cz/proceedings/Capek+Kolar.pdf |title=ČVUT.cz - Čapek, Kolář |access-date=2010-05-12 |url-status=dead |archive-url=https://web.archive.org/web/20110718170646/http://www.railway2007.fd.cvut.cz/proceedings/Capek+Kolar.pdf |archive-date=2011-07-18 }}</ref>

==== Historic ====
In the past, many different types of bogie (truck) have been used under tramcars (e.g. [[J. G. Brill Company|Brill]], Peckham, maximum traction).  A maximum traction truck has one driving axle with large wheels and one nondriving axle with smaller wheels.  The bogie pivot is located off-centre, so more than half the weight rests on the driving axle.

=== Hybrid systems ===
[[File:Bogie-metro-Meteor-p1010692.jpg|thumb|[[Mockup]] of the pneumatic bogie system of an [[MP 89]] carriage used on the [[Paris Métro Line 14|''Meteor'' metro]], showing the two [[Wheelset (rail transport)#Special wheelsets|special wheelsets]]<ref name=truck/>]]
The retractable stadium roof on Toronto's [[Rogers Centre]] used modified off-the-shelf train bogies on a circular rail. The system was chosen for its proven reliability.

[[Rubber-tyred metro]] trains use a specialised version of railway bogies. Special flanged steel wheels are behind the rubber-tired running wheels, with additional horizontal guide wheels in front of and behind the running wheels, as well. The unusually large flanges on the steel wheels guide the bogie through standard [[railroad switch]]es, and in addition keep the train from [[derailment|derailing]] in case the tires [[Flat tire|deflate]].<ref name=truck>{{cite web|url=http://www.infovisual.info/05/050_en.html|title=Truck (bogie) - Visual Dictionary|first=Bernard|last=Dery|website=www.infovisual.info|access-date=8 May 2018|url-status=live|archive-url=https://web.archive.org/web/20160616154008/http://infovisual.info/05/050_en.html|archive-date=16 June 2016}}</ref>

=== Variable gauge axles ===
{{main|Variable gauge}}
To overcome [[break of gauge|breaks of gauge]] some bogies are being fitted with variable gauge axles (VGA) so that they can operate on two different gauges.  These include the [[SUW 2000]] system from [[ZNTK Poznań]].