Editing Bogie

{{Short description|Chassis for wheels and suspension under vehicles}}
{{About|wheeled chassis for vehicles|carriages|railroad car|other uses|Bogie (disambiguation)|and|Bogey (disambiguation){{!}}Bogey}}
{{Distinguish|Boogie|Bogi}}
{{More citations needed|date=September 2022}}
{{Use dmy dates|date=November 2023}}
{{Use British English|date=November 2014}}
[[File:Seitenkipper-Ua4201-Drehgestell.jpg|thumb|upright=1.2|Bogie on a Czech Railways side-tipper car]]
{{Train topics}}

A '''bogie''' ({{IPAc-en|ˈ|b|oʊ|ɡ|i}} {{Respell|BOH|ghee}})<!-- Sound does not work. --> (or '''truck''' in North American English) comprises two or more [[Wheelset (rail transport)|wheelsets]] (two [[Railroad wheel|wheels]] on an [[axle]]), in a frame, attached under a vehicle by a pivot. Bogies take various forms in various modes of transport. A bogie may remain normally attached (as on many [[railroad car]]s and [[semi-trailer]]s) or be quickly detachable (as for a [[dolly (trailer)|dolly]] in a [[road train]] or in railway [[bogie exchange]]). It may include [[Suspension (vehicle)|suspension]] components within it (as most rail and trucking bogies do), or be solid and in turn be suspended (as are most bogies of [[continuous track|tracked]] vehicles). It may be mounted on a [[swivel]], as traditionally on a railway carriage or locomotive, additionally jointed and sprung (as in the [[landing gear]] of an [[airliner]]), or held in place by other means (centreless bogies).{{Citation needed|date=November 2023}}

Although ''bogie'' is the preferred spelling and first-listed variant in various dictionaries,<ref name="MWCD">{{Citation | author = Merriam-Webster | author-link = Merriam-Webster | title = Merriam-Webster's Collegiate Dictionary | publisher = Merriam-Webster |url=http://unabridged.merriam-webster.com/collegiate/bogie |postscript=.}}</ref><ref name="AHD5">{{Citation |author=Houghton Mifflin Harcourt |author-link=Houghton Mifflin Harcourt |title=American Heritage Dictionary of the English Language |edition=5th |publisher=Houghton Mifflin Harcourt |url=https://ahdictionary.com/word/search.html?q=bogie&submit.x=0&submit.y=0 |postscript=. |url-status=dead |archive-url=https://web.archive.org/web/20150714054614/https://ahdictionary.com/word/search.html?q=bogie&submit.x=0&submit.y=0 |archive-date=2015-07-14 |access-date=2014-11-24 }}</ref><ref name="OxfordDictionaries">{{Citation | author = Oxford Dictionaries Online | author-link = OxfordDictionaries.com | title = Oxford Dictionaries Online | publisher = [[Oxford University Press]] | url = http://www.oxforddictionaries.com/definition/english/bogie?searchDictCode=all | postscript = . | url-status = dead | archive-url = https://web.archive.org/web/20141202033058/http://www.oxforddictionaries.com/definition/english/bogie?searchDictCode=all | archive-date = 2014-12-02 }}</ref> '''bogey''' and '''bogy''' are also used.<ref name="MWCD" /><ref name="AHD5" />

== 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]].

== Radial steering truck ==
Radial-steering trucks, also known as radial bogies, allow the individual axles to align with curves in addition to the bogie frame as a whole pivoting. For non-radial bogies, the more axles in the assembly, the more difficulty it has negotiating curves, due to [[flange|wheel flange to rail]] friction.  For radial bogies, the wheel sets actively steer through curves, thus reducing wear at the [[flange|wheel's flange-to-rail]] interface and improving adhesion.

In the US, radial steering has been implemented in [[Electro-Motive Diesel|EMD]] and [[GE Transportation|GE]] locomotives. The EMD version, designated HTCR, was made standard equipment for the [[EMD SD70 series|SD70 series]], first sold in 1993. The HTCR in operation had mixed results and relatively high purchase and maintenance costs.  EMD subsequently introduced the HTSC truck, essentially the HTCR stripped of radial components. GE introduced their version in 1995 as a buyer option for the [[GE AC4400CW|AC4400CW]] and later [[GE Evolution Series|Evolution Series]] locomotives. However, it also met with limited acceptance because of its relatively high purchase and maintenance costs, and customers have generally chosen GE Hi-Ad standard trucks for newer and rebuilt locomotives.
<gallery mode="packed" heights="150">
File:CP9112 SD90MAC.jpg|EMD HTCR radial steering trucks on an [[EMD SD90MAC|EMD SD9043MAC]]
File:FSRR 01.jpg|GE radial steering trucks on a [[GE AC4400CW]]
</gallery>

[[File:Glenelg Railway Company clerestory-roofed, 30-window passenger car with Cleminson underframe.jpg|thumb|350px|An [[w:Gilbert Car Company|American-built]] [[5 ft 3 in gauge railways#Installations|broad-gauge]] passenger car in [[South Australia]], one of six fitted with Cleminson self-steering axles; pictured in 1890, ten years after their purchase]]
A 19th century configuration of self-steering axles on [[rolling stock]] established the principle of radial steering. The Cleminson system<ref>{{cite web|url=https://patents.google.com/patent/US511685A/en |title=US511685A |date=26 December 1893 |website=[[Google Patents]] |access-date=29 October 2024}}</ref> involved three axles, each mounted on a frame that had a central pivot; the central axle could slide transversely. The three axles were connected by linkages that kept them parallel on the straight and moved the end ones radially on a curve, so that all three axles were continually at right angles to the rails.<ref>{{cite book|title=Little coastal railways of the Adelaide Plains 1873–1929 |first=David |last=Mack |date=1986 |location=Adelaide |publisher=self-published |page=29 |isbn=0 85904 041 0}}</ref> The configuration, invented by British engineer John James Davidge Cleminson, was first granted a patent in the [[UK]] in 1883.<ref>{{Cite journal|url=https://www.icevirtuallibrary.com/doi/pdf/10.1680/imotp.1897.19461|publisher=ICE Virtual Library| doi=10.1680/imotp.1897.19461 |accessdate=2022-01-28| title=Obituary. James Lyons-Cleminson, 1840-1896 | journal=Minutes of the Proceedings of the Institution of Civil Engineers | year=1897 | volume=127 | issue=1897 | pages=379–380 | url-access=subscription }}</ref> The system was widely used on British narrow-gauge rolling stock, such as on the [[Isle of Man Railway rolling stock|Isle of Man]] and [[Manx Northern Railway]]s.<ref>{{cite web|url=http://www.festipedia.org.uk/wiki/Cleminson_Flexible_Six-Wheeled_Waggon|title=Cleminson flexible six-wheeled waggon - Festipedia|website=www.festipedia.org.uk|access-date=27 October 2024|url-status=live|archive-url=https://web.archive.org/web/20160317160428/https://www.festipedia.org.uk/wiki/Cleminson_Flexible_Six-Wheeled_Waggon|archive-date=17 March 2016}}</ref> The [[Holdfast Bay railway line|Holdfast Bay Railway Company]] in [[South Australia]], which later became the Glenelg Railway Company, purchased Cleminson-configured carriages in 1880 from the American [[Gilbert Car Company|Gilbert & Bush Company]] for its {{Track gauge|1600mm|comma=off}} broad-gauge line.

== Articulated bogie ==
{{Main|Jacobs bogie}}
[[File:Sprinter-bogie+articulation.jpg|thumb|Articulated bogie on an [[Sprinter (rail service)|NCTD Sprinter]] [[Siemens Desiro|Siemens Desiro VT642]]]]
An '''articulated bogie''' (aka Jakob-type) is any one of a number of bogie designs that reduce weight, increase passenger comfort, and allow [[railway]] equipment to safely turn sharp corners, while reducing or eliminating the "screeching" normally associated with metal wheels rounding a bend in the rails. There are a number of such designs, and the term is also applied to train sets that incorporate articulation in the vehicle, as opposed to the bogies themselves.

If one considers a single bogie "up close", it resembles a small rail car with axles at either end. The same effect that causes the bogies to rub against the rails at longer radius causes each of the pairs of wheels to rub on the rails and cause the screeching. Articulated bogies add a second pivot point between the two [[axle]]s ([[Wheelset (rail transport)|wheelsets]]) to allow them to rotate to the correct angle even in these cases.

== Articulated lorries (tractor-trailers) ==
<!-- This section has nothing to do with [[locomotives]] or other [[railroad car]]s and no such article should be redirected to this section -->
In [[Road transport#Trucking and haulage|trucking]], a bogie is the subassembly of axles and wheels that supports a [[semi-trailer]], whether permanently attached to the frame (as on a single trailer) or making up the [[dolly (trailer)|dolly]] that can be hitched and unhitched as needed when hitching up a second or third semi-trailer (as when [[semi-trailer|pulling doubles]] or [[road train|triples]]).

== Tracked vehicles ==
Some [[tank]]s and other [[Caterpillar track|tracked]] vehicles have bogies as external suspension components (see [[suspension (vehicle)#Armoured fighting vehicle suspension|armoured fighting vehicle suspension]]). This type of bogie usually has two or more road wheels and some type of sprung suspension to smooth the ride across rough terrain. Bogie suspensions keep much of their components on the outside of the vehicle, saving internal space. Although vulnerable to [[antitank]] fire, they can often be repaired or replaced in the field.

== Aircraft bogies ==
{{Main|Landing gear}}

== See also ==
===Articles on bogies and trucks===
{{Div col|colwidth=20em}}
* [[Arnoux system]]
* [[Bissel bogie]]
* [[Blomberg B]]
* [[Gölsdorf axle]]
* [[Jacobs bogie]]
* [[Krauss-Helmholtz bogie]]
* [[Lateral motion device]]
* [[Mason Bogie]]
* [[Pony truck]]
* [[Rocker-bogie]]
* [[Scheffel bogie]]
* [[Schwartzkopff-Eckhardt bogie]]
* [[Syntegra]]
{{div col end}}

===Related topics===
{{Div col|colwidth=20em}}
* [[Caster]]
* [[Dolly (trailer)|Dolly]]
* [[Flange]]
* [[List of railroad truck parts]]
* [[Luttermöller axle]]
* [[Road–rail vehicle]]
* [[Skateboard truck]]
* [[Spring (device)]]
* [[Timmis system]], an early form of coil spring used on railway axles.
* [[Trailing wheel]]
* [[Wheel arrangement]]
* [[Wheelbase#Rail|Wheelbase]]
* [[Wheelset (rail transport)|Wheelset]]
{{Div col end}}

== References ==
{{Reflist|30em}}

== Further reading ==
* {{cite book|last=Baur|first=Karl Gerhard|title=Drehgestelle - Bogies|year=2006|publisher=EK-Verlag|location=Freiburg i.B.|isbn=978-3-88255-147-1}} {{in lang|de|en}}

== External links ==
{{Commons category|Bogies of rail vehicles|Bogie}}
{{Wiktionary}}

*{{cite EB1911|wstitle=Bogie |volume=4 |short=x}}
*[http://www.infovisual.info/05/050_en.html Truck (bogie) with tyres]
*[https://web.archive.org/web/20060823034931/http://www.rtu.mmu.ac.uk/pubs/Iwnicki%20Grassie%20Kik%20-%20Track%20Settlement%20prediction%20using%20computer%20simulation%20tools.pdf   Track modelling]
*[http://www.railway-technical.com/trains/rolling-stock-index-l/bogies.html Bogies/Trucks]
* [https://web.archive.org/web/20160304045504/http://www.sctco.com/pdf/sect_1.pdf Barber truck parts]
* [https://www.wheel-rail-seminars.com/archives/2015/pc-papers/PC-06%20May19PrinciplesCourse_7.pdf Suspension systems]
* [https://rskr.irimee.in/sites/default/files/Locomotive%E2%80%99s%20bogies.pdf Locomotive’s Bogies & Components]
{{Locomotive running gear}}
{{Authority control}}

[[Category:Bogie| ]]
[[Category:Locomotive parts]]
[[Category:Rail technologies]]
[[Category:Vehicle technology]]