Editing 4-6-4 (section)

==Overview==
===Tender locomotives===
The 4-6-4 [[tender (rail)|tender locomotive]] was first introduced in 1911 and throughout the 1920s to 1940s, the wheel arrangement was widely used in North America and to a lesser extent in the rest of the world. The type combined the basic design principles of the [[4-6-2]] type with an improved [[boiler]] and larger [[Firebox (steam engine)|firebox]] that necessitated additional support at the rear of the locomotive. In general, the available [[tractive effort]] differed little from that of the 4-6-2, but the steam-raising ability was increased, giving more power at speed. The 4-6-4 was best suited to high-speed running across flat terrain. Since the type had fewer [[driving wheel]]s than [[carrying wheels]], a smaller percentage of the locomotive's weight contributed to traction, compared to other types. Like the 4-6-2, it was well suited for high speed passenger trains, but not for starting heavy freight trains and slogging on long sustained grades, where more pairs of driving wheels are better.

The first 4-6-4 tender locomotive in the world was a four-cylinder [[compound locomotive]], designed by [[Gaston du Bousquet]] for the [[Chemins de fer du Nord]] in [[France]] in 1911. Since it was designed for the [[Paris]]-[[Saint Petersburg]] express, it was named the Baltic after the [[Baltic Sea]], which was a logical extension of the naming convention that started with the [[4-4-2 (locomotive)|4-4-2]] and 4-6-2.<ref name="Reed">Reed, Brian. (1972). ''Loco Profile, Nord Pacifics''. Windsor: Profile Publications.</ref>

The first 4-6-4 in the United States of America, J-1a #5200 of the [[New York Central Railroad]], was built in 1927 to the railroad's design by the [[American Locomotive Company]] (ALCO). There, the type was named the [[New York Central Hudson|Hudson]] after the [[Hudson River]]. They are also designed to pull 16-18 passenger cars in passenger service.<ref name="Hudson Type">{{Cite web |url=http://www.steamlocomotive.com/hudson/ |title=4-6-4 "Hudson" Type Locomotives |access-date=2012-03-06 |archive-url=https://web.archive.org/web/20080127121700/http://www.steamlocomotive.com/hudson/ |archive-date=2008-01-27 |url-status=dead }}</ref>

The world speed record for steam locomotives was held by a 4-6-4 at least twice. In 1934, the [[Milwaukee Road]]'s [[Milwaukee Road class F6|class F6]] no. 6402 reached {{convert|103.5|mph|km/h|abbr=off}} and, in 1936, the German class 05.002 reached {{convert|124.5|mph| km/h|abbr=off}}. That record was broken by the British 4-6-2 [[LNER Class A4 4468 Mallard|no. 4468 ''Mallard'']] on 3 July 1938, when it reached {{convert|126|mph|km/h|abbr=off}}, still the world speed record for steam traction.<ref name="DB Museum">{{Cite web |url=http://www.deutschebahn.com/site/dbmuseum/en/exhibitions/vehicles/05__001__e.html |title=DB Museum in Nuremberg - Germany's fastest steam locomotive |access-date=2010-01-26 |archive-url=https://web.archive.org/web/20100827082556/http://www.deutschebahn.com/site/dbmuseum/en/exhibitions/vehicles/05__001__e.html |archive-date=2010-08-27 |url-status=dead }}</ref>

===Tank locomotives===
The 4-6-4T was also a fairly common [[wheel arrangement]] for passenger [[tank locomotive]]s. As such, it was essentially the tank locomotive equivalent of a {{nowrap|[[4-6-0]]}} tender locomotive, with water tanks and a coal bunker supported by four trailing wheels instead of in a tender. In New Zealand, some 4-6-4T locomotives (the Wab class) were tank versions of [[4-6-2]] locomotives (of the Ab class).

The first known 4-6-4 tank locomotive was rebuilt from a [[Natal Government Railways]] (NGR) [[South African Class C 4-6-0T|K&S Class]] [[4-6-0|4-6-0T]] which was modified in 1896 to enable it to run equally well in either direction on the [[Colony of Natal|Natal]] South Coast line, where no turning facilities were available at the time. This sole locomotive later became the [[South African Class C2 4-6-4T|Class C2]] on the [[South African Railways]] (SAR). The first known locomotive class to be designed with a 4-6-4T wheel arrangement, the NGR's [[South African Class E 4-6-4T|Class F]] tank locomotive, was based on this modified locomotive and built by [[Neilson & Company|Neilson, Reid & Company]] in 1902. These became the Class E on the SAR in 1912.<ref name="Holland 1">{{Holland-Vol 1|pages=87–89, 96–98, 127–129, 135–137}}</ref><ref name="Paxton-Bourne">{{Paxton-Bourne|pages=23, 28–30, 33}}</ref>

One [[DRG Class 61|streamlined 4-6-4T]] was built for the [[Deutsche Reichsbahn]] in 1935.