Editing Tank classification (section)

==Size classifications==
Tanks are often referred to by weight-based classifications such as 'light', 'medium' or 'heavy', and by extension the role that this size of tank was suitable for. There were many names given to different tank types, and similar names did not assure similar design goals. Some light tanks were relatively slow, and some were fast. Some heavy tanks had large-calibre, low-velocity, anti-infantry bunker-busters, and some had high-velocity anti-tank guns.  Furthermore, expected weights for a given tank type vary over time; a medium tank of 1939 could weigh less than a light tank of 1945.

While originally based on weight, the light, medium, and heavy classifications expanded based on tactical use.  They now have other meanings than just weight, including relation to [[tank gun|gun]] size, the amount of [[vehicle armour|armour]], and, most importantly, tactical role.  Post-war in 1948 [[France]], [[Canada]], and the [[United States]] agreed to classify tanks as light gun, medium gun, or heavy gun.

After World War II, less expensive [[armoured car (military)|armoured car]]s and more specialised tracked vehicles gradually took over the roles of light tanks.

Heavy tanks were shown to be incapable of keeping up with mobile warfare, but advances in engine, weapon, and armour technology allowed medium tanks to acquire the best characteristics of heavy tanks, allowing them to fulfil multiple roles on the battlefield.  The ultimate in mobility, firepower, and protection were rolled into the main battle tank (MBT).  In 1957, the Fourth Tripartite Armour Conference recommended to replace medium and heavy tanks with a single class – Main Battle Tanks.<ref name="MBT commission">{{cite book|title=Cold war, hot science: applied research in Britain's defence laboratories, 1945–1990|year=2002|publisher=NMSI Trading Ltd|isbn=1-900747-47-2|editor1-first=Robert|editor1-last=Bud|editor2-first=Philip|editor2-last=Gummett}} [https://books.google.com/books?id=HMx_6FtHBcUC&pg=PA123 p.123]</ref>

===World War I===
{{main|Tanks in World War I}}

In World War I, the first tank, the {{convert|28|LT|t ST|0|adj=on}} British [[Mark I tank|Mark I]], was designed for supporting infantry by crossing trenches and attacking machine-gun posts. This became known as a heavy tank alongside other, lighter, types.

A lighter British tank introduced into service in 1918, at {{convert|14|LT|t ST|1}} and armed with machine guns only was given the designation [[Medium Mark A Whippet|"Tank, Medium Mark A"]] and known as the "Whippet".

The two-man {{convert|7|t|LT ST|0|adj=on}} French [[Renault FT]] was known as a light tank.

[[Super-heavy tank|Super-heavy]] breakthrough tanks such as the [[Char 2C]] ({{convert|69|t|LT ST|0|abbr=on|disp=or}}) or the [[K Panzerkampfwagen|''K-Wagen'']] ({{convert|120|t|LT ST|0|abbr=on|disp=or}}) were nearly completed before the war ended. In comparison, the current British MBT, the [[Challenger 2]], weighs some {{convert|60|t|LT ST|0|abbr=on}}.

===Interbellum===
{{main|Tanks of the interwar period}}
British tank designs in the immediate post-World War I era were developments along the same design as the Mark A and were named as Mediums being around {{convert|18|LT|t ST|0|abbr=on}}. The first tank to enter service that broke with the design was known as the "Vickers Light Tank" (it weighed about {{convert|12|LT|t ST|0|disp=or}}). It was renamed as the [[Vickers Medium Mark I|Medium Mark I]] in 1924 as the earlier heavy and medium tanks went out of service and lighter tanks – {{convert|5|LT|t ST|0|abbr=on}} or less – came into service.<ref>B. T. White, "British tanks 1915–1945", p. 35</ref>

===World War II===

{{main|Tanks in World War II}}

In World War 2, Light, Medium, and Heavy tank applications to different roles were incorporated into doctrine.  In the US, [[light tank]]s were expected to be used ahead of the main force, [[medium tank]]s to accompany the main thrust of attack, and by-their-nature slower [[heavy tank]]s being brought up to deal with any more significant opposition.  In practice, US heavy tanks saw limited use due to the capacity limits of most dockyard equipment, preventing their delivery to the theatres of operation.  This left a role-based classification, the [[tank destroyer]], to evolve from the need to move artillery pieces and set ambushes for axis tanks. A variety of [[super-heavy tank]]s were also designed during World War II, although none ever saw combat or construction due to their impracticality.

The British retained some light tanks from the interbellum period, but otherwise moved to a new role based classification scheme.
<!-- if anyone knows SIZE based classifications for the other armies, please include them -->

Other countries started to move to a more role-based approach, for example, by categorizing tanks into cruiser tanks, breakthrough tanks, and fast tanks. The tanks themselves are still often referred to by light, medium and heavy weights based on the actual weight or the equivalent role (for example, a cruiser tank may be light weight but is used in a similar role to a medium).  This continued until multi-role vehicles became available.

===Modern===
Light tanks, such as the [[PT-76]], continue to play an important role in [[tank warfare]], however many are being replaced with [[Infantry fighting vehicle|IFVs]] and [[Armoured car (military)|armoured cars]]. The light tank is still more used than [[main battle tank]]s in many armies for various reasons: financial, terrain-related (muddy landscape and dense foliage), or doctrinal dependence on airborne divisions.  Many light vehicles, such as the British [[Combat Vehicle Reconnaissance (Tracked)]] series ([[FV101 Scorpion]], [[FV107 Scimitar]]) are used primarily for reconnaissance, but retain the tank capabilities.{{citation needed|date=August 2017}}

Medium and Heavy tanks were used in the early stages of the cold war, but have gradually been phased out by the multi-role Main Battle Tank.  Heavy tanks grew to the point of being logistically problematic, such as the Conqueror and IS-3, while the MBT became capable of filling their battlefield role in a comparatively Medium form-factor.  In most cases, the Heavy tanks grew so large that they could not be transported by rail, and could not be supported by common bridges.