2-6-6-0

First known tank engine version
First known tank engine version
First use	1904
Country	Dutch East Indies (Indonesia)
Locomotive	SS Class 520 (DKA CC10)
Railway	Staatsspoorwegen
Designer	Sachsische Maschinenfabrik (Hartmann)
Builder	Sachsische Maschinenfabrik

Equivalent classifications
Equivalent classifications
UIC class	(1C)C, (1'C)C
French class	130+030
Turkish class	34+33
Swiss class	3/4+3/3
Russian class	1-3-0+0-3-0

2-6-6-0
	Front of locomotive at left
	NGR Mallet 2-6-6-0 of 1909
UIC class
Equivalent classifications
UIC class	(1C)C, (1'C)C
French class	130+030
Turkish class	34+33
Swiss class	3/4+3/3
Russian class	1-3-0+0-3-0
First use
First known tank engine version
First use	1904
Country	Dutch East Indies (Indonesia)
Locomotive	SS Class 520 (DKA CC10)
Railway	Staatsspoorwegen
Designer	Sachsische Maschinenfabrik (Hartmann)
Builder	Sachsische Maschinenfabrik
First use
First known tender engine version
First use	1909
Country	Colony of Natal
Locomotive	NGR 2-6-6-0, SAR Class MA
Railway	Natal Government Railways
Designer	American Locomotive Company
Builder	American Locomotive Company

Under the Whyte notation for the classification of steam locomotives by wheel arrangement, 2-6-6-0 is a locomotive with one pair of unpowered leading wheels, followed by two sets of three pairs of powered driving wheels and no trailing wheels. The wheel arrangement was principally used on Mallet-type articulated locomotives. Some tank locomotive examples were also built, for which various suffixes to indicate the type of tank would be added to the wheel arrangement, for example 2-6-6-0T for an engine with side-tanks.